Answer:
In this example, if the emf of the 4 V battery is increased to 15 V and the rest of the circuit remains the same, what is the potential difference Vab?
The image of the circuit has been attached
At 12 emf Vab = 9.5 V
At 15 emf Vab = 12.94 V
Explanation:
Kirchhoff loop rule states that the sum of the currents coming into a junction equals the sum of the currents going out of a junction. That is to say that the sum is equal to zero.
Calculations
The voltage in a circuit can be calculated using the expression;
V= IR .............1
since the Applying Kirchhoff rule to the circuit we have;
Calculating Vab (the voltage across ab) when the emf is 12 v
let us obtain the value of the current flowing across the circuit using equation 1 and Kirchhoff loop rule
+12 - (I x 2) -(I x 3)-(I x 4)-(4)-(I x 7) = 0
I = 8/16 = 0.5 A
calculating the voltage across Vab we have;
Vab = 4V + (I x 7) + (I x 4)
Vab = 4V + (0.5 x 7) + (0.5 x 4)
Vab = 4 +3.5+2
Vab = 9.5 V
at 12v emf Vab is 9.5V
calculating Vab at 15 emf value using equation and also Kirchhoff's loop rule we have;
+15 - (I x 4) -(I x 3)-(I x 2)-(12)-(I x 7) = 0
I = 3/16
I =0.1875 A
Vab = 15 V -(I x 7) - (I x 4)
Vab = 15 - ( 0.1875 x 4)-(0.1875 x 7)
Vab = 15 - 0.75-1.3125
Vab = 12.94 V
A helicopter lifts a 72 kg astronaut 15 m vertically from the ocean by means of a cable. The acceleration of the astronaut is g/10. How much work is done on the astronaut by (a) the force from the helicopter and (b) the gravitational force on her? Just before she reaches the helicopter, what are her (c) kinetic energy and (d) speed?
Answer:
a) [tex]F_H=776.952\ N[/tex]
b) [tex]F_g=706.32\ N[/tex]
c) [tex]v=5.4249\ m.s^{-1}[/tex]
d) [tex]KE=1059.48\ J[/tex]
Explanation:
Given:
mass of the astronaut, [tex]m=72\ kg[/tex]vertical displacement of the astronaut, [tex]h=15\ m[/tex]acceleration of the astronaut while the lift, [tex]a=\frac{g}{10} =0.981\ m.s^{-2}[/tex]a)
Now the force of lift by the helicopter:
Here the lift force is the resultant of the force of gravity being overcome by the force of helicopter.
[tex]F_H-F_g=m.a[/tex]
where:
[tex]F_H=[/tex] force by the helicopter[tex]F_g=[/tex] force of gravity[tex]F_H=72\times 0.981+72\times9.81[/tex]
[tex]F_H=776.952\ N[/tex]
b)
The gravitational force on the astronaut:
[tex]F_g=m.g[/tex]
[tex]F_g=72\times 9.81[/tex]
[tex]F_g=706.32\ N[/tex]
d)
Since the astronaut has been picked from an ocean we assume her initial velocity to be zero, [tex]u=0\ m.s^{-1}[/tex]
using equation of motion:
[tex]v^2=u^2+2a.h[/tex]
[tex]v^2=0^2+2\times 0.981\times 15[/tex]
[tex]v=5.4249\ m.s^{-1}[/tex]
c)
Hence the kinetic energy:
[tex]KE=\frac{1}{2} m.v^2[/tex]
[tex]KE=0.5\times 72\times 5.4249^2[/tex]
[tex]KE=1059.48\ J[/tex]
Answer:
Explanation:
mass of helicopter, m = 72 kg
height, h = 15 m
acceleration, a = g/10
(a) Work done by the force
Work, W = force due to helicopter x distance
W = m x ( g + a) x h
W = 72 ( 9.8 + 0.98) x 15
W = 11642.4 J
(b) Work done by the gravitational force
W = - m x g x h
W = - 72 x 9.8 x 15
W = - 10584 J
(c) Kinetic energy = total Work done
K = 11642.4 - 10584
K = 1058.4 J
(d) Let the speed is v.
K = 0.5 x m v²
1058.4 = 0.5 x 72 x v²
v = 5.42 m/s
Now the force of lift by the helicopter:
where:
force by the helicopter
force of gravity
b)
The gravitational force on the astronaut:
d)
Since the astronaut has been picked from an ocean we assume her initial velocity to be zero,
using equation of motion:
c)
Hence the kinetic energy:
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You are working with a team that is designing a new roller coaster-type amusement park ride for a major theme park. You are present for the testing of the ride, in which an empty 220 kg car is sent along the entire ride. Near the end of the ride, the car is at near rest at the top of a 101 m tall track. It then enters a final section, rolling down an undulating hill to ground level. The total length of track for this final section from the top to the ground is 250 m. For the first 230 m, a constant friction force of 350 N acts from computer-controlled brakes. For the last 20 m, which is horizontal at ground level, the computer increases the friction force to a value required for the speed to be reduced to zero just as the car arrives at the point on the track at which the passengers exit. (a) Determine the required constant friction force (in N) for the last 20 m for the empty test car.
Answer:
The required constant friction force for the last 20 m is 6,862.8 N
Explanation:
Energy Conversion
There are several ways the energy is manifested in our physical reality. Some examples are Kinetic, Elastic, Chemical, Electric, Potential, Thermal, Mechanical, just to mention some.
The energy can be converted from one form to another by changing the conditions the objects behave. The question at hand states some types of energy that properly managed, will make the situation keep under control.
Originally, the m=220 kg car is at (near) rest at the top of a h=101 m tall track. We can assume the only energy present at that moment is the potential gravitational energy:
[tex]E_1=mgh=220\cdot 9.8\cdot 101=217,756\ J[/tex]
For the next x1=230 m, a constant friction force Fr1=350 N is applied until it reaches ground level. This means all the potential gravitational energy was converted to speed (kinetic energy K1) and friction (thermal energy W1). Thus
[tex]E_1=K_1+W_1[/tex]
We can compute the thermal energy lost during this part of the motion by using the constant friction force and the distance traveled:
[tex]W_1=F_{r1}\cdot x_1=350\cdot 230=80,500\ J[/tex]
This means that the kinetic energy that remains when the car reaches ground level is
[tex]K_1=E_1-W_1=217,756\ J-80,500\ J=137,256\ J[/tex]
We could calculate the speed at that point but it's not required or necessary. That kinetic energy is what keeps the car moving to its last section of x2=20 m where a final friction force Fr2 will be applied to completely stop it. This means all the kinetic energy will be converted to thermal energy:
[tex]W_2=F_{r2}\cdot x_2=137,256[/tex]
Solving for Fr2
[tex]\displaystyle F_{r2}=\frac{137,256}{20}=6,862.8\ N[/tex]
The required constant friction force for the last 20 m is 6,862.8 N
To determine the required constant friction force for the last 20 m of the roller coaster ride, we consider the energy changes that occur. The work done by the friction force is equal to the loss in potential energy. By using the equation -mgh = -f x d, we can solve for the friction force.
Explanation:To determine the required constant friction force for the last 20 m of the roller coaster ride, we need to consider the energy changes that occur. As the car rolls downhill, it loses potential energy and gains kinetic energy. The work done by the friction force is equal to the loss in potential energy. Using the equation -m g h = - f x d, where m is the mass of the car, g is the acceleration due to gravity, h is the height of the track, f is the friction force, and d is the distance over which the force acts, we can solve for the friction force.
In this case, the mass of the car is 220 kg, the height of the track is 101 m, and the distance over which the force acts is 20 m. Plugging these values into the equation, we get:
-220 kg * 9.8 m/s² * 101 m = -f * 20 m
Solving for f, we find that the required constant friction force for the last 20 m of the ride is approximately 2151 N.
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You have a battery marked " 6.00 V 6.00 V ." When you draw a current of 0.207 A 0.207 A from it, the potential difference between its terminals is 5.03 V 5.03 V . What is the potential difference when you draw 0.523 A 0.523 A ?
Answer:
V= 3.55 V
Explanation:
As the potential difference between the battery terminals, is less than the rated value of the battery, this means that there is some loss in the internal resistance of the battery. We can calculate this loss, applying Ohm's law to the internal resistance, as follows:[tex]V_{rint} = I* r_{int}[/tex]
The value of the potential difference between the terminals of the battery, is just the voltage of the battery, minus the loss in the internal resistance, as follows:[tex]V = V_{b} - V_{rint} = 6.00 V - 0.207A* r_{int}[/tex]
We can solve for rint, as follows:[tex]r_{int} = \frac{V_{b} - V}{I} = \frac{6.00 V - 5.03V}{0.207A} = 4.7 \Omega[/tex]
When the circuit draws from battery a current I of 0.523A, we can find the potential difference between the terminals of the battery, as follows:[tex]V = V_{b} - V_{rint} = 6.00 V - 0.523A* 4.7 \Omega = 3.55 V[/tex]
As the current draw is larger, the loss in the internal resistance will be larger too, so the potential difference between the terminals of the battery will be lower.An electromagnetic wave is propagating towards the west in free space. At a certain moment the direction of the magnetic field vector associated with this wave points vertically upward.
What is the direction of the electric field vector?
A. vertical and pointing down.
B. vertical and pointing up.
C. horizontal and pointing north.
D. horizontal and pointing south.
E. horizontal and pointing east.
Answer:
The direction of the electric field vector is horizontal and pointing north.
Option (C) is correct option.
Explanation:
Given :
The direction of wave propagation is toward the west.
The direction of magnetic field vector is vertically upward.
According to the theory of electromagnetic wave propagation, the electric field and magnetic field is perpendicular to each other and the direction of propagation is also perpendicular to both electric and magnetic field vector.
⇒ [tex]\vec{E} + \vec{B} = \vec {k}[/tex]
From right hand rule, the fingers goes towards horizontal and pointing north and curl the finger goes towards vertically upward and thumb will give you the direction of wave propagation toward west.
Hence, the direction of electric field vector is horizontal and pointing north.
The correct direction of the electric field vector in an electromagnetic wave propagating to the west with an upward magnetic field is horizontal and pointing north, following the right-hand rule for perpendicularity and direction of electromagnetic waves.
Explanation:The subject of this question is the direction of the electric field vector in an electromagnetic wave that is propagating towards the west, with a magnetic field vector that points vertically upward. According to the properties of electromagnetic waves, the electric field (E) and magnetic field (B) are perpendicular to each other and to the direction of wave propagation. Therefore, if the magnetic field is pointing upward and the wave is moving west, the electric field must be pointing horizontally. Since the right-hand rule dictates that E x B gives the direction of wave propagation, and the wave is moving west, the electric field cannot be pointing east or west as it would not satisfy the right-hand rule. Thus, the electric field is either pointing north or south. To determine the correct direction between north and south, we rely on the right-hand rule: the fingers of the right hand point in the direction of E, the curled fingers point towards B, and the thumb points in the direction of the wave propagation (west in this case). If the magnetic field points up, and propagation is to the west, the electric field must be directed to the north. Therefore, the correct answer is C. horizontal and pointing north.
The average life span in the United States is about 70 years. Does this mean that it is impossible for an average person to travel a distance greater than 70 light years away from the Earth? (A light year is the distance that light travels in a year.) This is not a yes or no answer. Explain your reasoning.
Answer:
for the people of the Earth traveling they last much more than 70 years
Explanation:
In order to answer this answer we must place ourselves in the context of special relativity, which are the expressions for time and displacement since the speed of light has a finite speed that is the same for all observers.
The life time of the person is 70 years in a fixed reference system in the person this time we will call their own time (t₀), when the person is placed in a ship that moves at high speed, very close to the speed of the light the time or that an observer measures on Earth, the expression for this time is
t = t₀ 1 / √(1 - (v / c)²)
We see that if the speed of the ship is very close to the speed of light the
the value of the root of the denominator is very high, for which for the person on Earth it measures a very large time even when the person on the ship travels has a time within its 70 years of life
In concussion, for the people of the Earth traveling they last much more than 70 years
. Determine the horizontal and vertical components of reaction at the hinge A and the horizontal reaction at the smooth surface B caused by the water pressure. The plate has a width of 4 ft. Start your solution by presenting the appropriate FBD. rhow = 1.94 slug/ft3 .
Answer:
Please find attached file for complete answer solution and explanation of same question.
Explanation:
A vertical scale on a spring balance reads from 0 to 200 N . The scale has a length of 11.0 cm from the 0 to 200 N reading. A fish hanging from the bottom of the spring oscillates vertically at a frequency of 2.55 Hz .Ignoring the mass of the spring, what is the mass m of the fish?
Answer:
7.08 kg
Explanation:
Given:
Length of scale (x) = 11.0 cm = 0.110 m [1 cm = 0.01 m]
Range of scale is from 0 to 200 N.
Frequency of oscillation of fish (f) = 2.55 Hz
Mass of the fish (m) = ?
Now, range of scale is from 0 to 200 N. So, maximum force, the spring can hold is 200 N. For this maximum force, the extension in the spring is equal to the length of the scale. So, [tex]x = 0.11\ m[/tex]
Now, we know that, spring force is given as:
[tex]F=kx\\\\k=\frac{F}{x}[/tex]
Where, 'k' is spring constant.
Now, plug in the given values and solve for 'k'. This gives,
[tex]k=\frac{200\ N}{0.11\ m}=1818.18\ N/m[/tex]
Now, the oscillation of the fish represents simple harmonic motion as it is attached to the spring.
So, the frequency of oscillation is given as:
[tex]f=\frac{1}{2\pi}\sqrt{\frac{k}{m}}[/tex]
Squaring both sides and expressing it in terms of 'm', we get:
[tex]\frac{k}{m}=4\pi^2f^2\\\\m=\dfrac{k}{4\pi^2f^2}[/tex]
Now, plug in the given values and solve for 'm'. This gives,
[tex]m=\frac{1818.18\ N/m}{4\pi^2\times (2.55\ Hz)^2}\\\\m=\frac{1818.18\ N/m}{256.708\ Hz^2}\\\\m=7.08\ kg[/tex]
Therefore, the mass of the fish is 7.08 kg.
A conducting coil of 1785 turns is connected to a galvanometer, and the total resistance of the circuit is 43.9 Ω. The area of each turn is 4.50 10-4 m2. This coil is moved from a region where the magnetic field is zero into a region where it is nonzero, the normal to the coil being kept parallel to the magnetic field. The amount of charge that is induced to flow around the circuit is measured to be 9.33 10-3 C. Find the magnitude of the magnetic field.
Answer:
0.5099 T
Explanation:
We are given that
Number of turns=N=1785
Resistance of circuit, R=[tex]43.9\Omega[/tex]
Area of each turn,[tex]A=4.5\times 10^{-4} m^2[/tex]
Charge , q=[tex]9.33\times 10^{-3} C[/tex]
We have to find the magnitude of the magnetic field.
We know that magnetic field, [tex]B=\frac{qR}{NA}[/tex]
Substitute the values
Magnetic field, B=[tex]\frac{9.33\times 10^{-3}\times 43.9}{1785\times 4.5\times 10^{-4}}=0.5099 T [/tex]
Hence, the magnitude of the magnetic field=0.5099 T
A ball on the end of a string is whirled around in a horizontal circle of radius 0.300 m. The plane of the circle is 1.50 m above the ground. The string breaks and the ball lands 2.10 m (horizontally) away from the point on the ground directly beneath the ball's location when the string breaks. Find the radial acceleration of the ball during its circular motion. Magnitude
To calculate the radial acceleration of a ball in circular motion, derive its velocity using the horizontal distance traveled upon string break and use the centripetal acceleration formula.
Explanation:The question provided involves calculating the radial acceleration of a ball in circular motion before the string breaks. To solve this, we must understand that the radial or centripetal acceleration formula is a = v^2 / r, where a is the centripetal acceleration, v is the velocity of the object in circular motion, and r is the radius of the circle.
However, the information given directly does not include the velocity v. We can derive the velocity using the horizontal distance the ball traveled after the string broke. Since the only force acting on the ball after the string breaks is gravity, the horizontal motion can be considered uniform. The formula distance = velocity x time (d = vt) can be rearranged to find the velocity (v = d/t). Using the principle of projectile motion, the time (t) it takes for the ball to hit the ground can be found using the formula derived from the vertical motion due to gravity: t = sqrt(2h/g), where h is the height above the ground and g is the acceleration due to gravity (9.81 m/s2).
Coming back to finding the radial acceleration, once we have the velocity, we simply substitute values into the centripetal acceleration formula. Note that the actual calculations were not performed as the goal here is to elucidate the strategy for solving the problem.
Final answer:
The radial acceleration of the ball during circular motion was calculated to be approximately 47.7 m/s².
Explanation:
To find the radial acceleration of the ball during its circular motion, we'll use the information provided about the ball's horizontal displacement after the string breaks.
In a situation where the string breaks and an object follows a projectile motion, the horizontal component of its initial velocity (vx) can be calculated using the horizontal displacement (d) and the time of flight (t). The formula for horizontal displacement is d = vx * t.
The time of flight (t) can be found using the vertical motion equations, considering that the ball drops 1.50 m. Since the ball is released from rest in the vertical direction, we have:
Vertical displacement (y): 1.50 m
Acceleration due to gravity (g): 9.81 m/s2
Initial vertical velocity (vy0): 0 m/s
Using the equation y = vy0 * t + 0.5 * g * [tex]t^2[/tex], we can solve for the time of flight (t), which will also be the same time the ball is moving horizontally since horizontal and vertical motions are independent.
Applying this equation to calculate the time (t):
1.50 = 0 + 0.5 * 9.81 * [tex]t^2[/tex]
t = sqrt(2 * 1.50 / 9.81)
t ≈ 0.553 s (rounded to three significant figures)
Now we can find the horizontal velocity (vx) using the horizontal distance (d):
2.10 = vx * 0.553
vx ≈ 3.80 m/s
The horizontal velocity of the ball at the instant the string breaks is the same as the tangential velocity of the ball while it was in circular motion. Therefore, we can calculate the radial or centripetal acceleration (ar) using the formula for centripetal acceleration:
ar = v2 / r
where v is the tangential velocity and r is the radius.
So:
ar = [tex](3.80 m/s)^2[/tex] / 0.300 m
ar ≈ 47.7 m/s2
The radial acceleration of the ball during its circular motion was approximately 47.7 [tex]m/s^2[/tex].
A rectangular coil of wire (a = 22.0 cm, b = 46.0 cm) containing a single turn is placed in a uniform 4.60 T magnetic field, as the drawing shows. The current in the loop is 10.0 A. Determine the magnitude of the magnetic force on the bottom side of the loop.
Explanation:
Below is an attachment containing the solution.
The magnitude of the magnetic force experienced by the bottom side of the rectangular coil, placed in a uniform magnetic field and carrying a current, is 21.16 N.
Explanation:The subject of this question relates to the interaction of a current-carrying wire in a magnetic field, a fundamental concept in physics. In this particular setup, the magnetic force on each segment of the rectangular coil can be determined by the formula: F = I (L × B), where F is the magnetic force, I is the current, L is the length of the wire and B is the magnetic field. But in this instance, we're specifically interested in the force exerted on the bottom side of the loop, for which the magnetic field and current are perpendicular to each other.
Therefore, the force is given by F = ILB. By substituting the given values into the equation—the length of the bottom side (b = 0.46 m), the magnitude of the current (I = 10 A), and the strength of the magnetic field (B = 4.60 T)—we obtain: F = (10 A)(0.46 m)(4.60 T) = 21.16 N.
So, the magnitude of the magnetic force on the bottom side of the loop is 21.16 N.
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A 2.03 kg book is placed on a flat desk. Suppose the coefficient of static friction between the book and the desk is 0.542 and the coefficient of kinetic friction is 0.294. How much force is needed to begin to move the book and how much force is needed to keep the book moving at a constant velocity
Answer:
Force is needed to begin to move the book and force needed to keep the book moving at a constant velocity is 10.78 N and 5.85 N.
Explanation:
Given :
Mass of book , M = 2.03 kg.
Coefficient of static friction , [tex]\mu_s=0.542 \ .[/tex]
Coefficient of kinetic friction , [tex]\mu_k=0.294\ .[/tex]
Force, required needed to begin to move the book ,
[tex]F=\mu_sN=\mu_s(mg)=0.542\times 2.03\times 9.8=10.78\ N.[/tex]
Now, We know kinetic friction acts when object is in motion .
Therefore , Force, required o keep the book moving at a constant velocity
[tex]F=\mu_kN=\mu_k(mg)=0.294\times 2.03\times 9.8=5.85\ N.[/tex]
Hence, this is the required solution.
A transformer supplies 60 watts of power to a device that is rated at 20 volts. The primary coil is connected to a 120-volt ac source. What is the current I1I1I_1 in the primary coil
Answer:
The current in the primary coil would be [tex]0.5\ A[/tex].
Explanation:
Given the power supplied by a transformer is 60 watts.
And the voltage in the primary coil is 120 Volts.
We need to find the current supply in the primary coil.
We will use the formula
[tex]P=V\times I[/tex]
Where,
[tex]P[/tex] is the power in Watts.
[tex]V[/tex] is the voltage in Volts.
[tex]I[/tex] is the current supply in Ampere.
[tex]I=\frac{P}{V}\\\\I=\frac{60}{120}\\ \\I=0.5\ A[/tex]
So, the current in the primary coil would be [tex]0.5\ A[/tex].
A proton moves at a speed of 1,140 m/s in a direction perpendicular to a magnetic field with a magnitude of 0.78 T. If the proton is replaced with an electron, how will the magnitude of the force change?
Answer:
1.42×10⁻¹⁶ N.
Explanation:
The force on a charge moving in a magnetic field is given as
F = qBvsin∅..................... Equation 1
Where F = Force on the charge, q = charge, B = Magnetic Field, v = speed, ∅ = angle between the magnetic field and the speed
Given: B = 0.78 T, v = 1140 m/s, ∅ = 90° ( Perpendicular) q = 1.60 × 10⁻¹⁹ C.
Substitute into equation 1
F = 0.78(1140)(1.60 × 10⁻¹⁹)sin90°
F = 1.42×10⁻¹⁶ N.
Hence the force on the charge = 1.42×10⁻¹⁶ N.
A series RL circuit includes a 6.05 V 6.05 V battery, a resistance of R = 0.655 Ω , R=0.655 Ω, and an inductance of L = 2.55 H. L=2.55 H. What is the induced emf 1.43 s 1.43 s after the circuit has been closed?
Answer:
The induced emf 1.43 s after the circuit is closed is 4.19 V
Explanation:
The current equation in LR circuit is :
[tex]I=\frac{V}{R} (1-e^{\frac{-Rt}{L} })[/tex] .....(1)
Here I is current, V is source voltage, R is resistance, L is inductance and t is time.
The induced emf is determine by the equation :
[tex]V_{e}=L\frac{dI}{dt}[/tex]
Differentiating equation (1) with respect to time and put in above equation.
[tex]V_{e}= L\times\frac{V}{R}\times\frac{R}{L}e^{\frac{-Rt}{L} }[/tex]
[tex]V_{e}=Ve^{\frac{-Rt}{L} }[/tex]
Substitute 6.05 volts for V, 0.655 Ω for R, 2.55 H for L and 1.43 s for t in the above equation.
[tex]V_{e}=6.05e^{\frac{-0.655\times1.43}{2.55} }[/tex]
[tex]V_{e}=4.19\ V[/tex]
Based on the calculations, the induced emf is equal to 4.19 Volts.
Given the following data:
Voltage = 6.05 V.Resistance = 0.655 Ω.Inductance = 2.55 H.Time = 1.43 seconds.How to determine the induced emf.In a RL circuit, current is given by this mathematical expression:
[tex]I=\frac{V}{R} (1-e^{\frac{Rt}{L} })[/tex]
Where:
I is the current.V is the source voltage.R is the resistance.L is the inductance.t is the time.For an induced emf in a circuit, we have:
[tex]E=L\frac{dI}{dt} \\\\E=L \times I \\\\E=L \times \frac{V}{R} (1-e^{\frac{-Rt}{L} })\\\\E=V e^{\frac{-Rt}{L} }\\\\E=6.05 e^{\frac{-0.655 \times 1.43}{2.55} }[/tex]
E = 4.19 Volts.
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Suppose a child drives a bumper car head on into the side rail, which exerts a force of 3400 N on the car for 0.400 s. (Assume the initial velocity is in the positive direction.)
(a)What impulse (in kg · m/s) is imparted by this force? (Indicate the direction with the sign of your answer.)
(b)Find the final velocity (in m/s) of the bumper car if its initial velocity was 3.30 m/s and the car plus driver have a mass of 200 kg. You may neglect friction between the car and floor. (Indicate the direction with the sign of your answer.)
Q2: Compare the kinetic energy of a 22,000 kg truck moving at 120 km/h with that of an 82.0 kg astronaut in orbit moving at 28,000 km/h.
Answer a) impulse is 1360 kg.m/s
Explanation: impulse is impact force times the time of impact
I = 3400 * 0.4 = 1360kg.m/s
Answer b) final velocity is 10.1m/s
Explanation: impulse is the change of momentum
I = m(v-u)
V and u are final and initial velocities respectively.
1360 = 200 (v - 3.3)
1360 = 200v - 660
V = (1360+660)÷200
V = 10.1m/s
Q2 answer is: astronaut has KE approximately 208 times that of the truck
Explanation :
KE = 0.5mv^2
For truck
KE = 11000 * 33.3^2 = 12197790J
For astronaut
KE = 42 * 7777.7^2 = 2540689926J
Comparing
2540689926/12197790 = 208.2
NB: speed has been converted to m/s by multiplying with 0.28 I.e 1000/3600
A chlorine and bromine atom are adsorbed on a small patch of surface (see sketch at right). This patch is known to contain possible adsorption sites. The and bromine atoms have enough energy to move from site to site, so they could be on any two of them. Suppose the atom desorbs from the surface and drifts away. Calculate the change in entropy. Round your answer to significant digits, and be sure it has the correct unit symbol.
Answer:
ΔS = - 3.74 × 10⁻²³ J/K = - 3.7 × 10⁻²³ to 2 s.f
Explanation:
The change in entropy for a system with changing allowable Microsystems is given as
ΔS = K In (W/W₀)
K = Boltzmann's constant = 1.381 × 10⁻²³ J/K
W₀ = initial number of microstates
To calculate this, how many ways can 2 atoms occupy 16 available microstates with order important?
That is, ¹⁶P₂ = 16!/(16 - 2)! = 16 × 15 = 240 microstates.
W = the number of microstates for Chlorine atom when Bromine atom desorps = 16 microstates.
ΔS = K In (W/W₀)
ΔS = (1.381 × 10⁻²³) In (16/240)
ΔS = (1.381 × 10⁻²³) × 2.7081
ΔS = - 3.74 × 10⁻²³ J/K
Entropy change is positive when an atom desorbs from a surface and drifts away, allowing for more freedom of movement and increasing the system's entropy.
Entropy change is a measure of disorder in a system. When an atom desorbs from a surface and drifts away, the change in entropy is positive as it increases the freedom of movement of the atom. This occurs because there are more possible locations for the atom to occupy, leading to an increase in entropy.
An elevator is moving down at a constant rate of 4 m/s. A person is standing on a scale that says the person weighs 80 N. When it reaches the bottom, it comes to a stop in 2 seconds.
During the stopping process, what is the reading on the scale?
Final answer:
During the elevator's deceleration, the scale reading would increase to approximately 96.3 N as the passenger experiences an upward acceleration.
Explanation:
During the stopping process of the elevator that is descending at 4 m/s and comes to a rest in 2 seconds, the reading on the scale will change due to the acceleration the passenger experiences while the elevator decelerates. The initial velocity v0 is -4 m/s (downwards) and the final velocity v is 0 m/s, as the elevator comes to a stop. The time t taken to stop is 2 seconds, so to find the acceleration, we use the formula a = (v - v0)/t.
This gives us an acceleration of (0 - (-4))/2 = 2 m/s2 upwards, since deceleration is a positive acceleration in the opposite direction of movement. A person's apparent weight on a scale is the normal force exerted by the scale, which can be calculated from Newton's second law, F = ma, where m is mass and a is the acceleration. In this case, the person's actual mass (m) can be deduced from their weight (W = mg), where g is the acceleration due to gravity (approximately 9.81 m/s2).
By rearranging the weight formula, m = W/g, we find m = 80 N / 9.81 m/s2 ≈ 8.16 kg. Now, we add the elevator's upward acceleration to the gravity, so the total acceleration the person feels is (g + a) = 9.81 m/s2 + 2 m/s2 = 11.81 m/s2. Applying F = ma gives us the scale reading: F = 8.16 kg × 11.81 m/s2 ≈ 96.3 N.
The correct answer is that the reading on the scale during the stopping process is 160 N.
When the elevator comes to a stop, it decelerates, which means there is an upward acceleration. According to Newton's second law, the net force acting on an object is equal to the mass of the object times its acceleration ([tex]F_net = m * a[/tex]). In this case, the net force is the difference between the normal force and the gravitational force [tex](F_net = N - mg)[/tex], where mg is the weight of the person.
Given that the elevator decelerates at a rate of 4 m/s in 2 seconds, we can calculate the deceleration (a) as follows:
[tex]\[ a = \frac{\Delta v}{\Delta t} = \frac{4 \text{ m/s}}{2 \text{ s}} = 2 \text{ m/s}^2 \][/tex]
Now, we can set up the equation for the net force during deceleration:
[tex]\[ N - mg = m * a \][/tex]
Since the weight of the person (mg) is 80 N, we can substitute this value into the equation:
[tex]\[ N - 80 \text{ N} = m * 2 \text{ m/s}^2 \][/tex]
To find the normal force (N) during deceleration, we need to solve for N:
[tex]\[ N = m * 2 \text{ m/s}^2 + 80 \text{ N} \][/tex]
We know that when the elevator was moving at a constant rate, the normal force was equal to the weight of the person [tex](N_constant = 80 N).[/tex] During deceleration, the normal force must be twice the weight of the person to provide the additional force required to decelerate the person:
[tex]\[ N = 2 * 80 \text{ N} = 160 \text{ N} \][/tex]
Therefore, the reading on the scale during the stopping process is 160 N.
Consider a cylindric container with the radius of circle 50 cm and the length of 3 m. We fill this container with one mole of the oxygen gas O2 at the room temperature 20◦C. Assume it is an ideal gas. a) What is the density of the gas in the tank?
Explanation:
Below is an attachment containing the solution .
When she rides her bike, she gets to her first classroom building 36 minutes faster than when she walks. Of her average walking speed is 3 mph and her average biking speed is 12 mph, how far is it from her apartment to the classroom building
Answer:
[tex]d=2.4\ miles[/tex]
Explanation:
Given:
average walking speed, [tex]v_w=3\ mph[/tex]average biking speed, [tex]v_b=12\ mph[/tex]According to given condition:
[tex]t_w=t_b+\frac{36}{60}[/tex]
where:
[tex]t_w=[/tex] time taken to reach the building by walking
[tex]t_b=[/tex] time taken to reach the building by biking
We know that,
[tex]\rm time=\frac{distance}{speed}[/tex]
so,
[tex]\frac{d}{v_w} =\frac{d}{v_b} +\frac{36}{60}[/tex]
[tex]\frac{d}{3}=\frac{d}{12} +\frac{3}{5}[/tex]
[tex]d=2.4\ miles[/tex]
Answer:
The distance from her apartment to the classroom building is 2.4 miles.
Explanation:
Given that,
Time = 36 min
Walking average speed of her = 3 m/h
biking average speed of her = 12 m/h
If she takes n minutes to ride, then if the distance is d miles,
We need to calculate the distance
Using formula of time
[tex]t=t_{1}+t_{2}[/tex]
[tex]t=\dfrac{d}{v_{1}}+\dfrac{d}{v_{2}}[/tex]
Put the value into the formula
[tex]\dfrac{36}{60}=\dfrac{d}{3}-\dfrac{d}{12}[/tex]
[tex]d=\dfrac{36\times12}{60\times3}[/tex]
[tex]d=2.4\ miles[/tex]
Hence, The distance from her apartment to the classroom building is 2.4 miles.
The solar wind is a thin, hot gas given off by the sun. Charged particles in this gas enter the magnetic field of the earth and can experience a magnetic force. Suppose a charged particle traveling with a speed of 8.03 x 106 m/s encounters the earth's magnetic field at an altitude where the field has a magnitude of 1.62 x 10-7 T. Assuming that the particle's velocity is perpendicular to the magnetic field, find the radius of the circular path on which the particle would move if it were (a) an electron and (b) a proton.
Answer: a) r = 281m, b) r = 5.13×10^-7m
Explanation: From the question, we realised that the particle enters the earth magnetic field with it velocity perpendicular to the magnetic field thus making the particle have a circular motion.
The force exerted on a charge in a magnetic field perpendicular to the velocity of the particle is responsible for the centripetal force required to give the object it circular motion.
Magnetic force = centripetal force.
qvB = mv²/r
By dividing "v" on both sides, we have that
qB = mv/r
Above is the formulae that defines the circular motion of a particle in the earth's magnetic field
Where q = magnitude of electronic charge.
B = strength of magnetic field = 1.62×10^-7 T
v = speed of particle = 8.03×10^6 m/s
A) If the particle where to be an electron, q ( magnitude of electron) =1.609×10^-19c.
m = mass of electronic charge = 9.11×10^-31 kg.
By substituting these parameters into the formulae we have that
1.609×10^-19× 1.62×10^-7 = 9.11×10^-31 × 8.03×10^6/ r
By cross multiplying, we have that
1.609×10^-19× 1.62×10^-7 × r = 9.11×10^-31 × 8.03×10^6
r = 9.11×10^-31 × 8.03×10^6 / 1.609×10^-19× 1.62×10^-7
r = 7.32*10^(-24)/ 2.61×10^-26
r = 2.81×10²
r = 281m
B)
If the particle is proton, q = magnitude of a proton charge = 1.609×10^-19c,
m = mass of proton = 1.673×10^-27 kg
By substituting these parameters into the formulae we have that
1.609×10^-19× 1.62×10^-7 = 1.673×10^-27×8.03×10^6/ r
By cross multiplying, we have that
1.609×10^-19× 1.62×10^-7 × r = 1.673×10^-27× 8.03×10^6
r = 1.673×10^-27 × 8.03×10^6 / 1.609×10^-19× 1.62×10^-7
r = 1.34*10^(-32)/ 2.61×10^-26
r = 0.513×10^-6 m
r = 5.13×10^-7m
A supply plane needs to drop a package of food to scientists working on a glacier in Greenland. The plane flies 110 m above the glacier at a speed of 150 m/s . You may want to review (Page) . For help with math skills, you may want to review:
Answer:
The distance is 709.5 m.
Explanation:
Given that,
Speed = 150 m/s
Distance = 110 m
Suppose, How far short of the target should it drop the package?
We need to calculate the time
Using equation of motion
[tex]s=ut+\dfrac{1}{2}gt^2[/tex]
[tex]t^2=\dfrac{2s}{g}[/tex]
Where, g = acceleration due to gravity
t = time
Put the value into the formula
[tex]t=\sqrt{\dfrac{2\times110}{9.8}}[/tex]
[tex]t=4.73\ sec[/tex]
We need to calculate the distance
Using formula of distance
[tex]d= vt[/tex]
Put the value into the formula
[tex]d=150\times4.73[/tex]
[tex]d=709.5\ m[/tex]
Hence, The distance is 709.5 m.
Two identical balls are thrown from the top of a building with the same speed. Ball 1 is thrown horizontally, while ball 2 is thrown at an angle above the horizontal. Neglecting air resistance, which ball will have the greatest speed when hitting the ground below?
Answer:
They both have the same speed when hitting the ground below
Explanation:
Conservation of the Mechanical Energy
In the absence of external non-conservative forces, the total mechanical energy of a particle is conserved or is kept constant.
The mechanical energy is the sum of the potential gravitational and kinetic energies, i.e.
[tex]\displaystyle M=mgh+\frac{mv^2}{2}[/tex]
When the first ball is launched at the top of the building of height h, at a speed vo, the mechanical energy is
[tex]\displaystyle M=mgh+\frac{mv_o^2}{2}[/tex]
When the ball reaches ground level (h=0) the mechanical energy is
[tex]\displaystyle M'=\frac{mv_f^2}{2}[/tex]
Equating M=M'
[tex]\displaystyle mgh+\frac{mv_o^2}{2}=\frac{mv_f^2}{2}[/tex]
We could solve the above equation for vf but it's not necessary because we have derived this relation regardless of the direction of the initial speed. It doesn't matter if it's launched with an angle above the horizontal, directly horizontal, or even directly downwards, the final speed is always the same.
It can also be proven with the exclusive use of the kinematic equations.
Note: The speed is the same for both balls, but not the velocity since the direction of the final velocity will be different in each case. Its magnitude is the same for all cases.
Answer: They both have the same speed when hitting the ground below
A thermometer reading 65° F is placed in an oven preheated to a constant temperature. Through a glass window in the oven door, an observer records that the thermometer reads 110° F after 1 2 minute and 140° F after 1 minute. How hot is the oven?
The temperature of the oven is 200°F
Explanation:
Given-
We have to apply Newton's law of cooling or heating
[tex]\frac{dT}{dt} = k ( T - Tm)\\\\\frac{dT}{T - Tm} = kdt[/tex]
On Integrating both sides, we get
[tex]T = Tm + Ce^k^t[/tex]
On putting the value,
T(0) = 65°F
[tex]65 = Tm + C\\C = 65 - Tm\\\\T = Tm + (65 - Tm) e^k^t[/tex]
After 1/2 minute, thermometer reads 110°F. So,
[tex]110 = Tm + (65 - Tm)e^0^.^5^k[/tex] - 1
After 1 minute, thermometer reads 140°F. So,
[tex]140 = Tm + (65 - Tm)e^k[/tex] - 2
Dividing equation 2 by 1:
[tex]e^k^-^0^.^5^k = \frac{140 - Tm}{110 - Tm} \\\\e^0^.^5^k = \frac{140 - Tm}{110 - Tm}[/tex] - 3
From 1 we have,
[tex]e^0^.^5^k = \frac{110 - Tm}{65 - Tm}[/tex]
Putting this vale in eqn 3. We get,
[tex]\frac{110 - Tm}{65 - Tm} = \frac{140 - Tm}{110 - Tm}[/tex]
[tex](110-Tm)^2 = (140-Tm) (65-Tm)\\\\12100 + Tm^2 - 220Tm = 9100 - 140Tm - 65Tm + Tm^2\\\\3000 - 220Tm = -205Tm\\\\3000 = 15Tm\\\\Tm = 200[/tex]
Therefore, the temperature of the oven is 200°F
The Temperature ( hotness ) of the oven is ; 200°F
Given data :
Initial thermometer reading ( To ) = 65°F
Thermometer reading after 1/2 minute ( T1/2 ) = 110°F
Thermometer reading after 1 minute ( T1 ) = 140°F
Temperature of oven ( Tm ) = ?
Determine the Temperature of the Oven
To determine the temperature of the oven we will apply Newton's law of heating and cooling.
[tex]\frac{dT}{dt} = K(T -Tm )[/tex] ( Integrating the expression we will have )
T = Tm + [tex]Ce^{kt}[/tex] ---- ( 1 )
where k = time
at T = 0 equation becomes
65 = Tm + C
∴ C = 65 - Tm
Back to equation ( 1 )
T = Tm + ( 65 -Tm )[tex]e^{kt}[/tex] ---- ( 2 )
After 1/2 minute equation 2 becomes
110 = Tm + ( 65 - Tm )[tex]e^{0.5k}[/tex] ---- ( 3 )
After 1 minute equation 2 becomes
140 = Tm + ( 65 - Tm )[tex]e^{k}[/tex] ---- ( 4 )
Next step : Divide equation 4 by equation 3
[tex]e^{0.5k} = \frac{140 - Tm}{110 - Tm}[/tex] ----- ( 5 )
Also From equation 3
[tex]e^{0.5k} = \frac{110 - Tm}{65 - Tm}[/tex] --- ( 6 )
Next step : Equating equations ( 5 ) and ( 6 )
( 110 - Tm )² = ( 140 - Tm )( 65 - Tm )
3000 - 220 Tm = -205Tm
∴ Tm = 3000 / 15 = 200°F
Hence we can conclude that the temperature ( hotness ) of the oven is 200°F.
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A straight wire carries a current of 238 mA from right to left. What is the magnetic field at a point 10.0 cm directly below the wire? Give the magnitude here, but make sure you can find the direction too
Answer:
B = (4.76 × 10⁻⁷) T
Explanation:
From Biot Savart's law, the magnetic field formula is given as
B = (μ₀I)/(2πr)
B = magnetic field = ?
I = current = 238 mA = 0.238 A
μ₀ = magnetic constant = (4π × 10⁻⁷) H/m
r = 10 cm = 0.1 m
B = [4π × 10⁻⁷ × 0.238)/(2π×0.1)]
B = (4.76 × 10⁻⁷) T
The direction of the magnetic field is in the clockwise direction wrapped around the current-carrying wire.
Hope this Helps!!!
Charge is distributed uniformly on the surface of a spherical balloon (an insulator). A point particle with charge q is inside. The electrical force on the particle is greatest when: a. it is near the inside surface of the balloon b. it is at the center of the balloonc. it is halfway between the balloon center and the inside surfaced. it is anywhere inside (the force is same everywhere and Is not zero)e. it is anywhere inside (the force is zero everywhere)
Answer:
e. it is anywhere inside (the force is zero everywhere)
Explanation:
The relation between the force and electric field is given as follows
[tex]\vec{F} = \vec{E}q[/tex]
where q is the charge inside, and E is the electric field inside the balloon created by the charge on the surface.
By Gauss' Law, the electric field inside the balloon created by the charges on the surface (excluding the charge q, since the electric field of the same charge cannot apply a force on the same charge) is zero.
[tex]\int \vec{E}d\vec{a} = \frac{Q_{enc}}{\epsilon_0}\\E4\pi r^2 = 0\\E = 0[/tex]
Since the external electric field inside the sphere is zero, then the force on the point charge is zero everywhere.
It is anywhere inside (the force is zero everywhere).
Electrical field on the surface of the charged sphereThe electrical field on the surface of the charged sphere is calculated by applying Coulomb law;
[tex]E = \frac{Qr}{4\pi \varepsilon _0R^3}[/tex]
Electric force is calculated as follows;
F = Eq
Electric field inside the charged sphereThe electric field inside the charged sphere is zero.
F = 0 x q = 0
Thus, we can conclude that, it is anywhere inside (the force is zero everywhere).
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Jen falls out of a tree and lands on a trampoline. The trampoline sags 60 cm before launching Jen back into the air. At the very bottom, where the sag is the greatest, is Jen’s acceleration upward, downward, or zero?
Answer:
At the very bottom, whnere the sag is the greatest, Jay’s acceleration is upward.
Explanation:
As Jay lands on the trampoline, Jay’s motion was dowward, the trampoline was opposing his motion and hence, caused him to reach an initial halt position. Afterwards, the trampoline causes Jay to move back into the air and therefore, the change in velocity vector act in upward direction. The acceleration vector is always align towards the change in velocity vector's direction.
You are riding a ferris wheel while sitting on a scale. A ferris wheel with radius 9.7 m and a period 32s. Find the scale reading for a 60kg person at the bottom of the ferris wheel and the top of the ferris wheel, assuming it moves at a constant rate.
Answer:
The scale reading at the top = 565.8N
The scale reading at the bottom = 610.44N
Explanation:
We are given:
t = 32seconds
R = 9.7meters
mass (m) = 60Kg
We take g as gravitational field = 9.8
Therefore, to find the scale reading (N) at the top, let's use the formula:
[tex] N_t = m (g - w^2 R) [/tex]
Where w = 2π/t
w = 2π/32 = 0.197
Substituting the figures into the equation, we have
[tex] N = 60 (9.8 - 0.197^2 * 9.7) [/tex]
N = 60 (9.8 - 0.37)
N = 60 * 9.43
Na = 565.8N
To find scalar reading at the bottom, we use;
[tex] N_b = m(g + w^2 R) [/tex]
= 60 (9.8 + 0.37)
= 60 * 10.17
[tex] N_b = 610.44 [/tex]
Answer:
The scale reading at the top is [tex]z_{top} = 565.6\mu N[/tex]
The scale reading at the bottom is [tex]z_{bottom} = 610.356\ N[/tex]
Explanation:
From the question
The radius is [tex]r = 9.7 m[/tex]
The period is [tex]T = 32sec[/tex]
The mass is [tex]m =60kg[/tex]
Generally the mathematical representation for angular velocity of the wheel is
[tex]\omega = \frac{2 \pi}{T}[/tex]
[tex]= \frac{2*3.142}{32}[/tex]
[tex]= 0.196 \ rad/sec[/tex]
The velocity at which the point scale move can be obtained as
[tex]v = r\omega[/tex]
[tex]= 9.7* 0.196[/tex]
[tex]= 1.9 m/s[/tex]
Considering the motion of the 60kg mass as shown on the first and second uploaded image
Let the z represent the reading on the scale which is equivalent to the normal force acting on the mass.
Now at the topmost the reading of the scale would be
[tex]mg - z_{top} =\frac{mv^2}{r} =m\omega^2r[/tex]
Where mg is the gravitational force acting on the mass and [tex]\frac{mv^2}{r}[/tex] is the centripetal force keeping the mass from spiraling out of the circle
Now making z the subject of the formula
[tex]z_{top} = mg - \frac{mv^2}{r}[/tex]
[tex]= m(g- \frac{v^2}{r})[/tex]
[tex]= 60(9.8 - \frac{1.9^2}{9.7} )[/tex]
[tex]= 565.6\mu N[/tex]
Now at the bottom the scale would be
[tex]z_{bottom}-mg = \frac{mv^2}{r} = m \omega^2r[/tex]
This is because in order for the net force to be in the positive y-axis (i.e for the mass to keep moving in the Ferris wheel) the Normal force must be greater than the gravitational force.
Making z the subject
[tex]z_{bottom}= mg +m\omega^2r[/tex]
[tex]z =m(g+\omega^2r)[/tex]
[tex]z= 60(9.8 + (0.196)^2 *(9.7))[/tex]
[tex]= 610.356\ N[/tex]
An 18-gauge copper wire (diameter 1.02 mm) carries a current with a current density of 1.40×106 A/m2 . Copper has 8.5×1028 free electrons per cubic meter
Calculate the current in the wire
Calculate the drift velocity of electrons in the wire.
Answer:
Part (a) current in the wire is 1.144 A
Part (b) the drift velocity of electrons in the wire is 1.028 x 10⁻⁴ m/s
Explanation:
Given;
diameter d = 1.02 mm
current density J = 1.40×10⁶ A/m²
number of electron = 8.5×10²⁸ electrons
Part (a) Current in the wire
I = J×A
Where A is area of the wire;
[tex]A = \frac{\pi d^2}{4} \\\\A = \frac{\pi (1.02X10^{-3})^2}{4} = 8.1723 X10^{-7} m^2[/tex]
I = 1.40 x 10⁶ x 8.1723 x 10⁻⁷
I = 1.144 A
Part (b) the drift velocity of electrons in the wire
[tex]V = \frac{J}{nq} = \frac{1.4X10^6}{8.5X10^{28} X 1.602X10^{-19}} = 1.028 X10^{-4} m/s[/tex]
We were given the
diameter = 1.02 mm
current density = 1.40×10⁶ A/m²
number of electron = 8.5×10²⁸ electrons
We can use the formula:
I = J×A
where I is current, J is density and A is area.
A = π d²
4
= π (1.02ₓ 10⁻³)² = 8.1723 x 10⁻⁷
4
I = J×A
I = 1.40 x 10⁶ x 8.1723 x 10⁻⁷
I = 1.144 A
The drift velocity of electrons in the wire.
V = J/ nq
= 1.4 ₓ 10⁶ / (8.5ₓ 10²⁸ₓ 1.602ₓ 10⁻¹⁹)
= 1.028ₓ 10⁻⁴ m/s
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A 100 kg box as showsn above is being pulled along the x axis by a student. the box slides across a rough surface, and its position x varies with time t according to the equation x=.5t^3 +2t where x is in meters and t is in seconds.
(a) Determine the speed of the box at time t=0
(b) determine the following as functions of time t.
Answer:
a) 2 m/s
b) i) [tex]K.E = 50 (1.5t^2 + 2) ^2\\[/tex]
ii) [tex]F = 3tm[/tex]
Explanation:
The function for distance is [tex]x = 0.5t ^3 + 2t[/tex]
We know that:
Velocity = [tex]v= \frac{d}{dt} x[/tex]
Acceleration = [tex]a= \frac{d}{dt}v[/tex]
To find speed at time t = 0, we derivate the distance function:
[tex]x = 0.5 t^3 + 2t\\v= x' = 1.5t^2 + 2[/tex]
Substitute t = 0 in velocity function:
[tex]v = 1.5t^2 + 2\\v(0) = 1.5 (0) + 2\\v(0) = 2[/tex]
Velocity at t = 0 will be 2 m/s.
To find the function for Kinetic Energy of the box at any time, t.
[tex]Kinetic \ Energy = \frac{1}{2} mv^2\\\\K.E = \frac{1}{2} \times 100 \times (1.5t^2 + 2) ^2\\\\K.E = 50 (1.5t^2 + 2) ^2\\[/tex]
We know that [tex]Force = mass \times acceleration[/tex]
[tex]a = v'(t) = 1.5t^2 + 2\\a = 3t[/tex]
[tex]F = m \times a\\F= m \times 3t\\F = 3tm[/tex]
The speed of the box at time t=0 is 0 m/s. The acceleration, displacement, and velocity functions of the box as a function of time are a(t) = 3t, x(t) = .5t^3 + 2t and v(t) = 1.5t^2 + 2 respectively.
Explanation:For part (a), the speed of the box at time t=0 can be found by taking the derivative of the position function x(t), which gives us the velocity function v(t). Therefore, v(t) = 1.5t^2 + 2 and v(0) = 0. Thus, the speed of the box at t=0 is 0 m/s.
For part (b), the box's acceleration at any time t can be found by taking the derivative of the velocity function v(t), which gives us the acceleration function a(t). Therefore, a(t) = 3t, the displacement function as a function of time is the original function x(t) = .5t^3 + 2t and the velocity function is as mentioned above, v(t) = 1.5t^2 + 2.
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. The current flowing through a tungsten-filament light bulb is determined to follow i(t) = 114 sin(100πt) A. (a) Over the interval defined by t = 0 and t = 2 s, how many times does the current equal zero amperes? (b) How much charge is transported through the light bulb in the first second?
Answer:
a) 201
b) 0
Explanation:
note:
solution is attached in word form due to error in mathematical equation. furthermore i also attach Screenshot of solution in word due to different version of MS Office please find the attachment
For the time interval from 0 to 2, sine wave reaches to zero for 201 times. Hence the current equals to zero for 201 times.
No charge transported through the light in the first second.
Given that, the current flowing through the bulb is [tex]I(t)=114 sin (100\pi t) \;\rm A[/tex].
The general equation of the current is,
[tex]I(t) =Asin(2\pi ft)[/tex]
So the frequency can be calculated as,
[tex]2\times \pi\times f\times t = 100\times \pi[/tex]
[tex]f =50 \;\rm Hz[/tex]
Hence the frequency of the sine wave is 50 Hz.
For the time interval from 0 to 2, the number of zero for the sine wave is,
[tex]No.\;of\; zero = (2\times50\times2 )+1[/tex]
[tex]No.\;of\;zero=201[/tex]
So, For the time interval from 0 to 2, sine wave reaches to zero for 201 times. Hence the current equals to zero for 201 times.
The charge can be calculated by the formula given below.
[tex]Q(t) = \int\limits^{t_1}_{t_2} {I(t)} \ dt[/tex]
[tex]Q(t)=\int\limits^1_0 {114sin(100\pi t)} \ dt[/tex]
[tex]Q(t) = \dfrac {-114cos(100\pi t)}{100\pi}[/tex]
[tex]Q(t) = \dfrac {-114cos(100\pi \times 1)}{100\pi}-\dfrac {-114cos(100\pi \times0)}{100\pi}[/tex]
[tex]Q(t)=0[/tex]
Hence, no charge transported through the light in the first second.
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