Answer:
Explanation:
Mass of car (M)=1200kg
Initial velocity (u)=20m/s
Stop after time (t)=3sec.
Come to stop implies that the final velocity is zero, v=0m/s
Using newton second law of motion
F=m(v-u)/t
Ft=m(v-u)
Since impulse is Ft
I=Ft
Then, I=Ft=m(v-u)
I=m(v-u)
I=1200(0-20)
I=1200×-20
I=-24,000Ns
The impulse delivered to the car by static friction is -24,000Ns
The impulse delivered to the car by static friction is -24,000Ns
Calculation of the impulse:Since A 1200-kg car, initially moving at 20 m/s, comes to a stop at a red light over a time of 3 s from the moment the driver hit the brakes.
Now here we used second law of motion of newton.
F=m(v-u)/t
Ft=m(v-u)
Since impulse is Ft
So,
I=Ft
Now
, I=Ft=m(v-u)
So,
I=m(v-u)
I=1200(0-20)
I=1200×-20
I=-24,000Ns
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URGENTLY NEED HELP WITH PHYSICS?
A vaulter is holding a horizontal 3.00-kg pole, 4.50 m long. His front arm lifts straight up on the pole, 0.750 from the end, and his back arm pushes straight down on the end of the pole. How much force does his back arm exert on the pole?
(Unit= N)
NEED HELP FAST
Answer:
58.8 N
Explanation:
Let 'F₁' be the force by front arm and 'F₂' be the force by back arm.
Given:
Mass of the rod (m) = 3.00 kg
Length of the pole (L) = 4.50 m
Acceleration due to gravity (g) = 9.8 m/s²
Distance of 'F₁' from one end of pole (d₁) = 0.750 m
'F₂' acts on the end. So, distance between 'F₁' and 'F₂' = 0.750 m
Now, weight of the pole acts at the center of pole.
Now, distance of center of pole from 'F₁' is given as:
d₂ = (L ÷ 2) - d₁
[tex]d_2=\frac{4.50}{2}-0.75=1.5\ m[/tex]
Now, as the pole is held horizontally straight, the moment about the point of application of force 'F₁' is zero for equilibrium of the pole.
So, Anticlockwise moment = clockwise moment
[tex]F_2\times d_1=mg\times d_2\\\\F_2=\frac{mg\times d_2}{d_1}[/tex]
Plug in the given values and solve for 'F₂'. This gives,
[tex]F_2=\frac{3.00\ kg\times 9.8\ m/s^2\times 1.5\ m}{0.75\ m}\\\\F_2=\frac{44.1}{0.75}=58.8\ N[/tex]
Therefore, the force exerted by the back arm on the pole is 58.8 N vertically down.
In a game of baseball, a player hits a high fly ball to the outfield. (a) Is there a point during the flight of the ball where its velocity is parallel to its acceleration? (b) Is there a point where the ball’s velocity is perpendicular to its acceleration? Explain in each case.
Final answer:
The velocity and acceleration vectors of a baseball can change during its flight. At the ball's maximum height, its velocity is parallel to its acceleration. There is no point where the ball's velocity is perpendicular to its acceleration.
Explanation:
In a game of baseball, the velocity and acceleration of a ball can change as it moves through the air. (a) Yes, there is a point during the flight of the ball where its velocity is parallel to its acceleration. This occurs when the ball reaches its maximum height. At this point, the ball stops moving upward and starts moving downward. Both the velocity and acceleration vectors are directed downward and therefore parallel to each other.
(b) No, there is no point during the flight of the ball where its velocity is perpendicular to its acceleration. The orientation of the velocity and acceleration vectors will always be either parallel or antiparallel to each other.
The GPS (Global Positioning System) satellites are approximately 5.18 mm across and transmit two low-power signals, one of which is at 1575.42 MHz (in the UHF band). In a series of laboratory tests on the satellite, you put two 1575.42 MHz UHF transmitters at opposite ends of the satellite. These broadcast in phase uniformly in all directions. You measure the intensity at points on a circle that is several hundred meters in radius and centered on the satellite. You measure angles on this circle relative to a point that lies along the centerline of the satellite (that is, the perpendicular bisector of a line which extends from one transmitter to the other). At this point on the circle, the measured intensity is 2.00 W/m^2.
Required:
What is the intensity at a point on the circle at an angle of 4.45° from the centerline?
Answer:
intensity at a point on the circle at an angle of 4.45° from the center line is 1.77 W/m².
Explanation:
See attached picture.
The intensity at a point on the circle at an angle of 4.45° from the centerline is approximately 4.00 W/m².
To find the intensity at a point on the circle at an angle of 4.45° from the centerline, we need to consider the interference pattern created by the two transmitters.
1. Wavelength Calculation:
The wavelength [tex](\(\lambda\))[/tex] of the transmitted signal can be calculated using the frequency [tex](\(f\))[/tex] and the speed of light c.
[tex]\[ \lambda = \frac{c}{f} \][/tex]
Given:
- [tex]\( c = 3 \times 10^8 \)[/tex] m/s (speed of light)
- [tex]\( f = 1575.42 \times 10^6 \)[/tex] Hz (frequency)
[tex]\[ \lambda = \frac{3 \times 10^8}{1575.42 \times 10^6} \approx 0.1902 \text{ meters} \][/tex]
2. Phase Difference Calculation:
The phase difference [tex](\(\Delta \phi\))[/tex] between the two waves at a point on the circle is determined by the path difference [tex](\(\Delta L\))[/tex] travelled by the waves.
The path difference is given by:
[tex]\[ \Delta L = d \sin(\theta) \][/tex]
where:
- d is the distance between the two transmitters (5.18 mm = 0.00518 m)
- [tex]\(\theta\)[/tex] is the angle from the centerline (4.45°)
[tex]\[ \Delta L = 0.00518 \sin(4.45^\circ) \approx 0.00518 \sin(0.0776) \approx 0.00518 \times 0.0775 \approx 0.0004019 \text{ meters} \][/tex]
The phase difference is:
[tex]\[ \Delta \phi = \frac{2 \pi \Delta L}{\lambda} = \frac{2 \pi \times 0.0004019}{0.1902} \approx 0.0133 \text{ radians} \][/tex]
3. Intensity Calculation:
The intensity at a given point due to two sources interfering constructively or destructively can be found using:
[tex]\[ I = I_0 \left(1 + \cos(\Delta \phi)\right) \][/tex]
Here, [tex]\(I_0\)[/tex] is the intensity when both waves interfere constructively at the centerline [tex](\(\theta = 0^\circ\))[/tex], which is given as 2.00 W/m^2.
[tex]\[ I = 2.00 \left(1 + \cos(0.0133)\right) \][/tex]
Since [tex]\(\cos(0.0133) \approx 0.9999\)[/tex]:
[tex]\(\cos(0.0133) \approx 0.9999\)[/tex]
Thus, the intensity at a point on the circle at an angle of 4.45° from the centerline is approximately 4.00 W/m².
A beam of protons is accelerated through a potential difference of 0.750 kVkV and then enters a uniform magnetic field traveling perpendicular to the field. You may want to review (Pages 641 - 643) . For related problem-solving tips and strategies, you may want to view a Video Tutor Solution of electron motion in a microwave oven. Part A What magnitude of field is needed to bend these protons in a circular arc of diameter 1.80 mm ? Express your answer in tesla to three significant figures. BpBp = nothing TT SubmitRequest Answer Part B What magnetic field would be needed to produce a path with the same diameter if the particles were electrons having the same speed as the protons? Express your answer in tesla to three significant figures. BeBe = nothing TT SubmitRequest Answer
Answer:
Explanation:
A force is provided by the magnetic field which perpendicular to both the velocity of the charge and magnetic field
F = qvB where B is the magnetic field in tesla, q is charge and v is velocity
The potential energy is transferred into kinetic energy
PE = Vq = 1/2 mv²
v = √(2Vq/ m)
charge on the proton = 1.602 × 10 ⁻¹⁹ C and mass of a proton = 1.673 × 10⁻²⁷
v = √ (( 2 × 1.602 × 10 ⁻¹⁹ C × 0.75 × 10³V ) / (1.673 × 10⁻²⁷)) = √( 1.4363 × 10¹¹ ) = 3.79 × 10⁵ m/s
The force of magnetic field produces centripetal force
qvB = mv² /R
where R radius = 1.80mm = 0.0018 m / 2 = 0.0009 m
qvB = ( m / R ) × (2qV /m)
cancel the common terms
vB = 2V / R
3.79 × 10⁵ m/s × B = 2 × 0.75 × 10³V / 0.0009 = 1.667 × 10⁶
B = 1.667 × 10⁶ / 3.79 × 10⁵ m/s = 4.40 T
b) magnetic field needed for the electron
qvB = mv² /R where m is the mass of an electron = 9.11 × 10⁻³¹ Kg
qB = mv/R
qB = ( 9.11 × 10⁻³¹ Kg × 3.79 × 10⁵ m/s) / 0.0009
qB = 3.8363 × 10 ⁻²²
B = 3.8363 × 10 ⁻²² / 1.602 × 10⁻¹⁹ kg = 0.0239 T
Determine the minimum work per unit of heat transfer from the source reservoir that is required to drive a heat pump with thermal energy reservoirs at 460 K and 540 K.
Answer:
The minimum work per unit heat transfer will be 0.15.
Explanation:
We know the for a heat pump the coefficient of performance ([tex]C_{HP}[/tex]) is given by
[tex]C_{HP} = \dfrac{Q_{H}}{W_{in}}[/tex]
where, [tex]Q_{H}[/tex] is the magnitude of heat transfer between cyclic device and high-temperature medium at temperature [tex]T_{H}[/tex] and [tex]W_{in}[/tex] is the required input and is given by [tex]W_{in} = Q_{H} - Q_{L}[/tex], [tex]Q_{L}[/tex] being magnitude of heat transfer between cyclic device and low-temperature [tex]T_{L}[/tex]. Therefore, from above equation we can write,
[tex]&& \dfrac{Q_{H}}{W_{in}} = \dfrac{Q_{H}}{Q_{H} - Q_{L}} = \dfrac{1}{1 - \dfrac{Q_{L}}{Q_{H}}} = \dfrac{1}{1 - \dfrac{T_{L}}{T_{H}}}[/tex]
Given, [tex]T_{L} = 460 K[/tex] and [tex]T_{H} = 540 K[/tex]. So, the minimum work per unit heat transfer is given by
[tex]\dfrac{W_{in}}{Q_{H}} = \dfrac{T_{H} - T_{L}}{T_{H}} = \dfrac{540 - 460}{540} = 0.15[/tex]
The minimum work required to operate a heat pump between two thermal reservoirs at 460 K and 540 K is determined using the performance coefficient equation, Kp = Qh/W = Th/(Th – Tc). The efficiency of a heat pump is determined by the energy it transfers through heat and the input work required. To improve efficiency, the temperature difference between the hot and cold reservoir should be maximized.
Explanation:The question pertains to the work-power balance in a heat pump operating between two thermal reservoirs. It involves the concept of thermal efficiency and the performance coefficient (Kp) of the heat pump.
Given the heat pump's thermal energy reservoirs at 460 K and 540 K, one can find the minimum work using the equation Kp = Qh/W = Th/(Th – Tc). Here, Th and Tc are the temperatures of the hot and cold reservoirs, respectively, Qh is the heat delivered to the hot reservoir, and W is the work done.
Such a heat pump operates on the principle of heat transfer of energy from a low-temperature reservoir to a high-temperature one, which requires input work. The quality of a heat pump is judged by the energy transferred by heat into the hot reservoir and the input work required.
The conservation of energy is not violated in this process, as the heat pump might extract energy from the ambient air or ground, contingent on its settings. Also, to improve the efficiency of the heat pump, the temperature of the hot reservoir should be elevated, and the cold reservoir should be lowered as per the Carnot efficiency equation.
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A 20~\mu F20 μF capacitor has previously charged up to contain a total charge of Q = 100~\mu CQ=100 μC on it. The capacitor is then discharged by connecting it directly across a 100-k\Omega100−kΩ resistor. At what point in time after the resistor is connected will the capacitor have 13.5~\mu C13.5 μC of charge remaining on it?
Explanation:
The given data is as follows.
C = [tex]20 \times 10^{-6} F[/tex]
R = [tex]100 \times 10^{3}[/tex] ohm
[tex]Q_{o} = 100 \times 10^{-6}[/tex] C
Q = [tex]13.5 \times 10^{-6} C[/tex]
Formula to calculate the time is as follows.
[tex]Q_{t} = Q_{o} [e^{\frac{-t}{\tau}][/tex]
[tex]13.5 \times 10^{-6} = 100 \times 10^{-6} [e^{\frac{-t}{2}}][/tex]
0.135 = [tex]e^{\frac{-t}{2}}[/tex]
[tex]e^{\frac{t}{2}} = \frac{1}{0.135}[/tex]
= 7.407
[tex]\frac{t}{2} = ln (7.407)[/tex]
t = 4.00 s
Therefore, we can conclude that time after the resistor is connected will the capacitor is 4.0 sec.
The required time to discharge the capacitor to a certain charge can be calculated by rearranging the exponential decay formula. The product of resistance and capacitance, known as the RC time constant, is a key value in this calculation. After substituting the values given into the formula, we get the required time.
Explanation:The time it takes for a capacitor to discharge through a resistor can be calculated using the formula for the decay of charge on a capacitive circuit: Q = Q0 * e-t/RC, where Q is the charge at time t, Q0 is the initial charge, R is the resistance and C is the capacitance. To find the time at which the charge will be 13.5 uC, we rearrange the formula to solve for time t: t = -RC * ln(Q/Q0).
Using the values of the problem: R = 100 kΩ = 100,000 Ω, C = 20 uF = 20*10-6 F, Q0 = 100 uC = 100*10-6 C, and Q = 13.5 uC = 13.5*10-6 C, substitute these values into the equation: t = -100,000 * 20*10-6 * ln (13.5/100). Hence, the time it takes for a capacitor to discharge to a specified charge can be calculated using exponential decay formula based on the capacitor's unique RC time constant.
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You are a member of a citizen's committee investigating safety in the high school sports program. You are interested in knee damage to athletes participating in the long jump (sometimes called the broad jump). The coach has her best long jumper demonstrate the event for you. He runs down the track and, at the take-off point, jumps into the air at an angle of 30 degrees from the horizontal. He comes down in a sand pit at the same level as the track 26 feet away from his take-off point. With what velocity (both magnitude and direction) did he hit the ground?
The velocity at which the long jumper landed can be computed by separating the jump into horizontal and vertical components, using the initial take-off angle and the horizontal distance. The horizontal and vertical velocities are combined to find the magnitude of the total landing velocity, and the arctangent of their ratio gives the direction.
Explanation:To determine the velocity at which the long jumper landed, we need to consider the projectile motion of the jump. There are two components of velocity to consider: the horizontal (vx) and the vertical (vy) at the point of landing.
First, the horizontal velocity (vx) can be found by dividing the total horizontal distance by the time of flight (t). The equation of horizontal motion is:
vx = d / t, where d is the horizontal distance.
The vertical velocity (vy) of the jumper when he lands will be the same magnitude but opposite in direction to the vertical velocity at take-off due to symmetry in projectile motion, assuming no air resistance. The vertical velocity at take-off can be calculated using the initial jump angle (Ө) and the initial velocity (v0).
Using the initial angle of 30°, the vertical component of the initial velocity at take-off (v0y) is:
v0y = v0 * sin(Ө).
Since the vertical motion is subject only to acceleration due to gravity (g), the final vertical velocity at landing (vy) will be v0y (but in the opposite direction).
The total landing velocity (v) is then found by combining these two components using the Pythagorean theorem:
v = √(vx^2 + vy^2).
The direction of the landing velocity is given by the angle made with the horizontal, found using the arctangent of the ratio of vy over vx:
θ = arctan(vy / vx).
These calculations would provide the magnitude and direction of the landing velocity.
A 1.50-V battery supplies 0.204 W of power to a small flashlight. If the battery moves 8.33 1020 electrons between its terminals during the time the flashlight is in operation, how long was the flashlight used
Answer:
981.41 secs
Explanation:
Parameters given:
Voltage, V = 1.5V
Power, P = 0.204W
Number of electrons, n = 8.33 * 10^20
First, we calculate the current:
P = I*V
I = P/V
I = 0.204/1.5 = 0.136A
The total charge of 8.33 * 10^20 electrons is:
Q = 8.33 * 10^20 * 1.6023 * 10^(-19)
Q = 133.47 C
Current, I, is given as:
I = Q/t
=> t = Q/I
t = 133.47/0.136 = 981.41 secs
In physics, power is calculated using the formula P = IV, where P is power, I is current, and V is voltage. By applying this formula, along with the relationship between charge, current, and time, the time the flashlight was used can be calculated.
Power is determined by the rate at which energy is transferred, calculated as P = IV where P is power, I is current, and V is voltage. In this scenario, the power supplied is 0.204 W from a 1.50-V battery. The formula P = IV can be rearranged to find the current flowing, which is 0.136 A.
To determine the time the flashlight was used, we can utilize the relationship between charge, current, and time: Q = It. Given 8.33 x 10^20 electrons moved, we need to convert this to Coulombs by recognizing that 1 electron has a charge of approximately 1.6 x 10^-19 C. By dividing the total charge by the current, we find the time t to be approximately 1.23 x 10^19 seconds.
A short circuit is a circuit containing a path of very low resistance in parallel with some other part of the circuit. Discuss the effect of a short circuit on the portion of the circuit it parallels. Use a lamp with a frayed line cord as an example.
Answer:
note:
please find the attachment
Explanation:
A frayed cord means that the insulation of the cord is worn out which exposes the cord and when it touches any other conductor a short circuit happens which is basically the flow of very high amount of current.
If we talk about the example of frayed cord, when such short circuit happens the lamp will not turn on and a massive amount of fault current will flow throughout the path of short circuit.
Now what happens?
There are two possibilities;
If there exists a circuit breaker, then no substantial amount of damage would be done since the circuit breaker will trip itself and open the circuit that eventually halts the fault current.If there is no circuit breaker, then this massive fault current will keep on accumulating that causes excessive heating of the conductors and also producing sparks which most probably would end up in a fire hazard.Choose the correct statement: Group of answer choices A proton tends to go from a region of low potential to a region of high potential. The potential of a negatively charged conductor must be negative. None of the other responses is correct. If V
Answer:
TRUE. The potential of a negatively charged conductor must be negative
Explanation:
Let's examine each statement
The positively charged proton moves in the direction of the electric field, the power and the electric field are related
ΔU = - E ds
[tex]U_{f}[/tex] - U₀ = - E ds
E = (U₀ –U_{f}) / s
To have a positive electric field the initial potential must be greater than the final potential, so the proton moves from a greater potential to a smaller one.
This statement is FALSE
The second statement
The potential has the same sign as the elective charge.
This statement is TRUE
A proton tends to move to a region of higher potential is False, while The potential of a negatively charged conductor must be negative is True.
Electric Potential:The proton is a positively charged particle and moves in the direction of the electric field lines.
In the case of a positive charge, the electric field lines are away from the charge, which will push the proton away.
We know that the potential is inversely proportional to distance.
Thus, as the proton moves away, it is going from a higher potential to a lower potential.
The same can be proven in the case of an electric field generated by a negative charge, by using proper sign convention.
So the statement that a proton tends to go from a region of low potential to a region of high potential is FALSE
The potential has the same sign as the electric charge.
So the statement that the potential of a negatively charged conductor must be negative is TRUE
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Point charges of 4.75 µC and −1.50 µC are placed 0.350 m apart. (Assume the negative charge is located to the right of the positive charge. Include the sign of the value in your answers.)
(a) Where can a third charge be placed so that the net force on it is zero?
_______ m to the right of the −1.50 µC charge
(b) What if both charges are positive?
_______ m to the right of the 1.50 µC charge
Answer:
Explanation:
Let the position of balance point be x distance from 1.5 µC on the right side . Balance point can not be on the left side or between the charges because in that case electric field by both the charges will be in the same direction .
For equilibrium of field
k x 4.75 µC / ( .35 +x )² - k x 1.5 µC / x ² = 0
4.75 / ( .35 +x )² = 1.5 / x²
( .35 +x )² / x² = 4.75 / 1.5
( .35 +x )² / x² = 3.167
( .35 +x ) / x = 1.78
.35 + x = 1.78 x
.78 x = .35
x = .45 m ( + ve ) to the right of 1.50 µC
b ) When both the charges are positive , balance point will lie in between them because , electric field will be in opposite direction .
For equilibrium of field
k x 4.75 µC / ( .35 - x )² = k x 1.5 µC / x ²
4.75 / ( .35 -x )² = 1.5 / x²
( .35 -x )² / x² = 4.75 / 1.5
( .35 -x )² / x² = 3.167
( .35 -x ) / x = 1.78
.35 -x = 1.78 x
2.78 x = .35
x = .126 m ( - ve ) to the right of 1.50 µC
Imagine you derive the following expression by analyzing the physics of a particular system: a=gsinθ−μkgcosθ, where g=9.80meter/second2. Simplify the expression for a by pulling out the common factor.
a.) a = g sinθ − μk g cosθ (no simplification should be performed on the expression in this situation)
b.) a = g (sinθ−μk cosθ)
c.) a = (9.80meter/second^2)sinθ −μk (9.80 meter/second^2)cosθ
Answer:
Explanation:
Analysis of structure gives
a=gsinθ−μkgcosθ
Notice that all the expression are right but we want to know of we can simplify the expression further.
We want to analyse if we can still further simplify the expression,
Inspecting the Right hand side of the equation, we notice that the acceleration due to gravity is common to both side, so we can bring it out i.e.
So option a is wrong because the expression can be simplified further to
a=g(sinθ−μkcosθ)
Option b is right and the best option.
Since we are given that, g=9.8m/s²
We can as well substitute that to option a
So we will have
a=9.8metre/second²(sinθ−μkcosθ)
Also option C is correct but it is not best inserting the values of g directly without simplifying the expression first
So it will have been the best option if it was written as
a=9.8metre/second²(sinθ−μkcosθ)
So the best option is B.
Sand falls from a conveyor belt at a rate of 30 m3m3/min onto the top of a conical pile. The height of the pile is always 3535 of the base diameter. Answer the following. a.) How fast is the height changing when the pile is 2 m high?
Explanation:
As the given data is as follows.
h = [tex]\frac{3}{5}d[/tex]
= [tex]\frac{3}{5} \times (2r)[/tex]
Also, we know that r = [tex]\frac{4}{3}h[/tex]
and Volume (V) = [tex]\frac{1}{3} \pir^{2}h[/tex]
= [tex]\frac{1}{3} \pi (\frac{4}{3}h)^{2} h[/tex]
= [tex]\frac{16}{27} \pi h^{3}[/tex]
And, [tex]\frac{dV}{dt} = \frac{3 \times 16}{27} \pi h^{2} \frac{dh}{dt}[/tex]
[tex]\frac{dV}{dt} = \frac{16}{9} \pi h^{2} \frac{dh}{dt}[/tex]
Putting the given values into the above formula as follows.
[tex]\frac{dV}{dt} = \frac{16}{9} \pi h^{2} \frac{dh}{dt}[/tex]
[tex]30 m^{3}/min = \frac{16}{9} \pi (2)^{2} \frac{dh}{dt}[/tex]
[tex]\frac{dh}{dt} = 1.343 m/min
or, = 134.3 cm/min (as 1 m = 100 cm)
thus, we can conclude that the height changing at 134.3 cm/min when the pile is 2 m high.
What is the critical angle θcritθcrittheta_crit for light propagating from a material with index of refraction of 1.50 to a material with index of refraction of 1.00?
Answer:
The critical angle is 41.8°.
Explanation:
The critical angle is [tex]\theta_1[/tex] for which the angle of refraction [tex]\theta_2[/tex] is 90°. From Snell's law we have
[tex]n_1sin (\theta_1 ) = n_2 sin(\theta_2)[/tex]
[tex]n_1sin (\theta_1 ) = n_2 sin(90^o)[/tex]
[tex]sin (\theta_1 ) = n_2/n_1,[/tex]
[tex]\theta_1 = sin^{-1}(\dfrac{n_2}{n_1} ).[/tex]
Putting in [tex]n_2 =1.00,[/tex] and [tex]n_1 = 1.50[/tex] we get:
[tex]\theta_1 = sin^{-1}(\dfrac{1.00}{1.500} ),[/tex]
[tex]\boxed{\theta_1 = 41.8^o}[/tex]
Thus, the critical angle is 41.8°.
Final answer:
The critical angle for light propagating from a material with an index of refraction of 1.50 to a material with an index of refraction of 1.00 is approximately 41.8 degrees.
Explanation:
The critical angle θcrit for light propagating from a material with an index of refraction (n1) of 1.50 to a material with an index of refraction (n2) of 1.00 is found using Snell's Law and the concept of total internal reflection. The formula to calculate the critical angle is θcrit = sin−1(n2/n1). Plugging in the values for the indices of refraction, we have θcrit = sin⁻¹(1.00/1.50).
Performing the calculation, we get:
θcrit = sin⁻¹(0.6667) ≈ 41.8°
Therefore, the critical angle for light traveling from a medium with an index of refraction of 1.50 to a medium with an index of refraction of 1.00 is approximately 41.8 degrees.
A piece of Nichrome wire has a radius of 6.5 104 m. It is used in a laboratory to make a heater that uses 4.00 102 W of power when connected to a voltage source of 120 V. Ignoring the effect of temperature on resistance, estimate the necessary length of wire.
Answer:
[tex]L=4.8*10^{17}m[/tex]
Explanation:
Given data
Power P=4.00×10²W
Radius r=6.5×10⁴m
Voltage V=120V
To find
Length of wire L
Solution
We know that resistance of wire can be obtained from
[tex]P=\frac{V_{2}}{R}\\ R=\frac{V_{2}}{P}[/tex]
We also know that R=pL/A solving the length noting that A=πr²
and using p=100×10⁻⁸Ω.m we find that
So
[tex]L=\frac{RA}{p}\\ L=\frac{\frac{(V^{2})}{P}(\pi r^{2}) }{p} \\L=\frac{V^{2}(\pi r^{2})}{pP}\\ L=\frac{(120V)^{2}\pi (6.5*10^{4} m)^{2} }{100*10^{-8}(4.00*10^{2} W) }\\ L=4.8*10^{17}m[/tex]
Final answer:
To calculate the length of Nichrome wire needed for a heating element using 400 W at 120 V, one determines the resistance and then uses it with the wire's cross-sectional area and resistivity. Approximately 41.45 meters of wire is required.
Explanation:
To estimate the necessary length of Nichrome wire for a laboratory heater, we start by calculating the resistance using the power and voltage supplied. The formula for power (P) in terms of voltage (V) and resistance (R) is P = V2 / R. Given P = 400 W and V = 120 V, the resistance can be calculated as follows:
R = V2 / P = (1202) / 400 = 36 Ω.
Next, we use the resistivity (ρ) of Nichrome and the cross-sectional area (A) of the wire to find the length (L). The formula R = ρL / A is applicable here, where ρ for Nichrome is approximately 1.10×10-6 Ω·m and A = πr2. The radius (r) given is 6.5×10-4 m, so:
A = π(6.5×10-4)2 = 1.33×10-6 m2.
Substituting the values into the formula, we get:
L = (R · A) / ρ = (36 · 1.33×10-6) / (1.10×10-6) ≠ 41.45 m.
Thus, approximately 41.45 meters of Nichrome wire is required for the heater to use 400 W of power at 120 V.
Coherent light with wavelength = 600 nm falls on two very narrow closely spaced slits and the interference pattern is observed on a screen that is 4 m from the slits. Near the center of the secreen the separation between adjacent maxima is 2 mm. What is the distance between the two slits?
Answer:
The distance between the two slits is 1.2mm.
Explanation:
The physicist Thomas Young establishes, through its double slit experiment, a relationship between the interference (constructive or destructive) of a wave, the separation between the slits, the distance between the two slits to the screen and the wavelength.
[tex]\Lambda x = L\frac{\lambda}{d} [/tex] (1)
Where [tex]\Lambda x[/tex] is the distance between two adjacent maxima, L is the distance of the screen from the slits, [tex]\lambda[/tex] is the wavelength and d is the separation between the slits.
If light pass through two slits a diffraction pattern in a screen will be gotten, at which each bright region corresponds to a crest, a dark region to a trough, as consequence of constructive interference and destructive interference in different points of its propagation to the screen.
Therefore, d can be isolated from equation 1.
[tex]d = L\frac{\lambda}{\Lambda x} [/tex] (2)
Notice that it is necessary to express L and [tex]\lambda[/tex] in units of millimeters.
[tex]L = 4m \cdot \frac{1000mm}{1m}[/tex] ⇒ [tex]4000mm[/tex]
[tex]\lambda = 600nm \cdot \frac{1mm}{1x10^{6}nm}[/tex] ⇒ [tex]0.0006mm[/tex]
[tex]d = (4000mm)\frac{0.0006mm}{2mm} [/tex]
[tex]d = 1.2mm[/tex]
Hence, the distance between the two slits is 1.2mm.
A projectile is launched with a launch angle of 55° with respect to the horizontal direction and with initial speed 78 m/s. How long does it remain in flight?
Answer:
The projectile is in air for 13.03 seconds.
Explanation:
Given that,
Angle of projection of the projectile, [tex]\theta=55^{\circ}[/tex]
Initial speed of the projectile, u = 78 m/s
To find,
We need to find the time of flight of the projectile.
Solution,
It is defined as the time taken by the projectile when it is in air. It is given by the formula as :
[tex]T=\dfrac{2u\ \sin\theta}{g}[/tex]
[tex]T=\dfrac{2\times 78\ \sin(55)}{9.8}[/tex]
T = 13.03 seconds
So, the projectile is in air for 13.03 seconds.
A piston–cylinder assembly contains 5.0 kg of air, initially at 2.0 bar, 30 oF. The air undergoes a process to a state where the pressure is 1.0 bar, during which the pressure–volume relationship is pV = constant. Assume ideal gas behavior for the air. Determine the work and heat transfer, in kJ.
Answer:
The work and heat transfer for this process is = 270.588 kJ
Explanation:
Take properties of air from an ideal gas table. R = 0.287 kJ/kg-k
The Pressure-Volume relation is PV = C
T = C for isothermal process
Calculating for the work done in isothermal process
W = P₁V₁ [tex]ln[\frac{P_{1} }{P_{2} }][/tex]
= mRT₁[tex]ln[\frac{P_{1} }{P_{2} }][/tex] [∵pV = mRT]
= (5) (0.287) (272.039) [tex]ln[\frac{2.0}{1.0}][/tex]
= 270.588 kJ
Since the process is isothermal, Internal energy change is zero
ΔU = [tex]mc_{v}(T_{2} - T_{1} ) = 0[/tex]
From 1st law of thermodynamics
Q = ΔU + W
= 0 + 270.588
= 270.588 kJ
To find the work and heat transfer in this process, we can apply the First Law of Thermodynamics. We can determine the work done using the equation pV = constant and calculate the heat transfer using the equation Q = CpdT.
To find the work and heat transfer in this process, we need to apply the First Law of Thermodynamics. The First Law states that the change in internal energy of a system is equal to the heat transfer into the system minus the work done by the system. In this case, since the process is isobaric (constant pressure), we can determine the work done by integrating the equation pV = constant. This will give us the equation W = p(Vf - Vi), where W is the work done, p is the pressure, and Vf and Vi are the final and initial volumes respectively.
Since the process is isobaric, the heat transfer can be calculated using the equation Q = CpdT, where Q is the heat transfer, Cp is the specific heat at constant pressure, and dT is the change in temperature. In this case, since the temperature change is not given explicitly, we can assume it to be the same as the change in internal energy, which gives us dT = dU/Cp.
By substituting the given values into the equations, we can calculate the work and heat transfer.
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You need to push a heavy box across a rough floor, and you want to minimize the average force applied to the box during the time the box is being pushed. Which method for pushing results in the minimum average force being applied to the box? a. Keep pushing the box forward at a steady speed, b. Push the box forward a short distance, rest, then repeat until finished, c. Push the box so that it accelerates forward at a constant rate.
When pushing the body it is necessary to break the frictional force generated by the floor. Once this frictional force is overcome, the body will begin to move. Ideally, if a constant velocity is maintained or close to this value, the acceleration that will be exerted will tend to be zero and therefore, by Newton's second law the value of the Force will also tend to minimum values.
Remember that this law tells us that
[tex]F= ma[/tex]
[tex]F= m \frac{\Delta v}{t}[/tex]
Therefore the best strategy is A. keep pushing the box forward at a steady speed
To minimize the average force applied to a box being pushed across a rough floor, you should keep pushing the box forward at a steady speed. This way, you're only balancing the frictional force, and there's no need for an extra force to accelerate the box.
Explanation:To minimize the average force applied to the box on a rough floor, you would opt for method a. Keep pushing the box forward at a steady speed. This option will ensure constant velocity, meaning that the net force on the box is zero. In this case, the force you're applying is just balancing the frictional force the box experiences due to the rough floor.
Contrastingly, methods b and c involve changing the box's velocity, which necessitates an acceleration. According to Newton's second law (F=ma), a force is required for acceleration. Thus, these methods will require a greater average force compared to method a.
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Two identical capacitors are connected parallel. Initially they are charged to a potential V0 and each acquired a charge Q0. The battery is then disconnected, and the gap between the plates of one capacitor is filled with a dielectric. (a) What is the new potential difference V across the capacitors. possible asnwers: V=(Vo)^2/[kQo+Vo), V=Vo/2k, V=Vo/2, V=kQo/Vo, V=2Vo/[k+1]
(b) If the dielectric constant is 7.8, calculate the ratio of the charge on the capacitor with the dielectric after it is inserted as compared with the initial charge.
Answer:
Explanation:
capacitance of each capacitor
C₀= Q₀ / V₀
V₀ = Q₀ / C₀
New total capacitance = C₀ ( 1 + K )
Common potential
= total charge / total capacitance
= 2 Q₀ / [ C₀ ( 1 + K ) ]
2 V₀ / ( 1 + K )
b )
Common potential = 2 x V₀ / ( 1 + 7.8 )
= .227 V₀
charge on capacitor with dielectric
= .227 V₀ x 7.8 C₀
= 1.77 V₀C₀
= 1.77 Q₀
Ratio required = 1.77
The new potential difference V across the capacitors and the ratio of the charge on the capacitor with the dielectric after it is inserted as compared with the initial charge can be calculated using specific equations.
Explanation:(a) What is the new potential difference V across the capacitors.
To find the new potential difference V across the capacitors, we need to consider the effect of adding a dielectric. The potential difference V is given by the equation:
V = Vo/2k
where Vo is the initial potential difference and k is the dielectric constant. In this case, since the dielectric constant is 7.8, we can substitute the values and calculate the new potential difference V.
(b) If the dielectric constant is 7.8, calculate the ratio of the charge on the capacitor with the dielectric after it is inserted as compared with the initial charge.
The ratio of the charge on the capacitor with the dielectric after it is inserted as compared with the initial charge can be calculated using the equation:
Q_with_dielectric / Q_initial = k
where Q_with_dielectric is the charge on the capacitor with the dielectric and Q_initial is the initial charge. Given that k is 7.8, we can substitute the values and calculate the ratio.
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Which of these atoms is most likely to share electrons with other atoms?
Answer:
your question is incomplete as the options are not given. I guess following is the complete question.
Which of these atoms is most likely to share electrons with other atoms?
a) chlorine (7 valence electrons)
b) calcium (2 valence electrons)
c) argon (8 valence electrons)
d) carbon (4 valence electrons)
e) potassium (1 valence electron)
The correct option is d) carbon (4 valence electrons)
Explanation:
Carbon has four electrons in its valence shell. In order to complete the 8 electrons in its valence shell carbon has to make four covalent bonds by sharing its four electrons with the other atom. Carbon atom will neither gain the electrons nor it losses the electrons to follow the octet rule. So in the above mentioned options carbon is the atom that will share maximum electrons.
→ Chlorine has 7 electrons, it will gain 1 electron. It will not do the sharing.
→ Calcium has 2 electrons, it will lost these 2 electrons to complete its shell.
→ Argon has already a completed shell. It will not react with other atom.
→ Potassium has only 1 valence electron which it will lose to complete its shell.
Answer: F
Explanation:
Water from a fire hose is directed horizontally against a wall at a rate of 53.9 kg/s and a speed of 38.9 m/s. Calculate the magnitude of the force exerted on the wall (in N), assuming the water's horizontal momentum is reduced to zero.
Answer:
[tex]F_{avg}=2096.71N[/tex]
Explanation:
As from the given data that:
m/Δt=53.9kg/s
The numerator is the mass and denominator is the change in time
Solve for change in velocity we have:
Δv=v₂-v₁
[tex]=0-38.9m/s\\=-38.9m/s[/tex]
Δv= -38.9m/s
From Newtons second law we know that:
F=ma
We can write this equation as:
Favg=(m/Δt)Δv
Substitute the given values
So
[tex]F_{avg}=(53.9kg/s)(-38.9m/s)\\F_{avg}=-2096.71N[/tex]
Using the average velocity formula.The answer will be positive, the negative only implies that force is coming away from the wall
[tex]F_{avg}=2096.71N[/tex]
(a) When a battery is connected to the plates of a 8.00-µF capacitor, it stores a charge of 48.0 µC. What is the voltage of the battery? V (b) If the same capacitor is connected to another battery and 192.0 µC of charge is stored on the capacitor, what is the voltage of the battery?
Answer:
a.6 V
b.24 V
Explanation:
We are given that
a.[tex]C=8\mu F=8\times 10^{-6} F[/tex]
[tex]1\mu =10^{-6} [/tex]
Q=[tex]48\mu C=48\times 10^{-6} C[/tex]
We know that
[tex]V=\frac{Q}{C}[/tex]
Using the formula
[tex]V=\frac{48\times 10^{-6}}{8\times 10^{-6}}=6 V[/tex]
b.[tex]Q=192\mu C=192\times 10^{-6} C[/tex]
[tex]V=\frac{192\times 10^{-6}}{8\times 10^{-6}}=24 V[/tex]
A dockworker applies a constant horizontal force of 90.0 N to a block of ice on a smooth horizontal floor. The frictional force is negligible. The block starts from rest and moves a distance 13.0 m in a time of 4.50 s .(a) What is the mass of the block of ice?
Answer:
The mass of the ice block is equal to 70.15 kg
Explanation:
The data for this exercise are as follows:
F=90 N
insignificant friction force
x=13 m
t=4.5 s
m=?
applying the equation of rectilinear motion we have:
x = xo + vot + at^2/2
where xo = initial distance =0
vo=initial velocity = 0
a is the acceleration
therefore the equation is:
x = at^2/2
Clearing a:
a=2x/t^2=(2x13)/(4.5^2)=1.283 m/s^2
we use Newton's second law to calculate the mass of the ice block:
F=ma
m=F/a = 90/1.283=70.15 kg
70.31kg
Explanation:Step I: Consider Newton's second law of motion which states that;
∑F = m x a;
Where;
∑F = net force acting on a body
m = the mass of the body
a = acceleration due to the force on the body.
Step II: Now to the question;
Since frictional force is negligible and the only force acting on the block of ice is the applied force by the dockworker, the net force on the body (block of ice) is the constant horizontal force. i.e
∑F = 90.0N
Also;
the block starts from rest and moves a distance (s) of 13.0m in a time (t) of 4.50s. Here, we can get the acceleration in that duration of time using one
the equations of motion as follows;
s = ut + [tex]\frac{1}{2}[/tex]at² ------------------------------(ii)
Where;
s = distance covered = 13.0m
u = initial velocity = 0 [since the block starts from rest]
t = time taken to cover the distance = 4.50s
a = acceleration of the body.
Substitute these values into equation (ii) as follows;
13.0 = 0(4.5) + [tex]\frac{1}{2}[/tex](a)(4.50)²
13.0 = 0 + [tex]\frac{1}{2}[/tex](a)(20.25)
13.0 = [tex]\frac{1}{2}[/tex](a)(20.25)
13.0 = 10.125a
Solve for a;
a = [tex]\frac{13.0}{10.125}[/tex]
a = 1.28m/s²
Step III: Now substitute the values of a = 1.28m/s² and ∑F = 90.0N into equation (i) as follows;
90.0 = m x 1.28
m = [tex]\frac{90.0}{1.28}[/tex]
m = 70.31
Therefore, the mass of the block of ice is 70.31kg
You are testing a new amusement park roller coaster with an empty car with a mass of 120 kg. One part of the track is a vertical loop with a radius of 12.0 m. At the bottom of the loop (point A) the car has a speed of 25.0 m/s and at the top of the loop (point B) it has speed of 8.00 m/s. As the car rolls from point A to point B, how much work is done by friction?
Answer:
[tex]W_f=-62460\ J[/tex]
Explanation:
Given that
mass of the car ,m = 120 kg
Radius ,R= 12 m
Speed at the bottom , u = 25 m/s
Speed at top ,v= 8 m/s
We know that
Work done by all the forces = Change in the kinetic energy
Work done by gravity + Work done by friction =Change in the kinetic energy
By taking point A as reference
[tex]m g \times (2R) + W_f=\dfrac{1}{2}mv^2-\dfrac{1}{2}mu^2[/tex]
Now by putting the values in the above equation we get
[tex]120\times 10\times 2\times 12+ W_f=\dfrac{1}{2}\times 120\times 8^2-\dfrac{1}{2}\times 120\times 25^2[/tex]
[tex]W_f=\dfrac{1}{2}\times 120\times 8^2-\dfrac{1}{2}\times 120\times 25^2-120\times 10\times 2\times 12\ J[/tex]
[tex]W_f=-62460\ J[/tex]
Therefore the work done by friction force will be -62460 J.
An initially uncharged 3.67 μF capacitor and a 8.01 k Ω resistor are connected in series to a 1.50 V battery that has negligible internal resistance. What is the initial current in the circuit, expressed in milliamperes?
Answer:
Explanation:
Given an RC series circuit
Initially uncharged capacitor
C=3.67 μF
Resistor R=8.01 k Ω=8010 ohms
Battery EMF(V)=1.5V with negligible internal resistance.
The initial current in the circuit?
At the beginning the capacitor is uncharged and it has a 0V, so all the voltage appears at the resistor,
Now using ohms law
V=iR.
i=V/R
i=1.5/8010
i=0.000187A
1mA=10^-3A
Therefore, 1A = 1000mA
i=0.187 milliamps
The initial current in the circuit is 0.187 mA
Answer:
The initial current is 0.0187 mA.
Explanation:
Given that
capacitance is given as 3.67 x 10⁻⁶ F
resistance is given as 8010 Ω
voltage across the circuit is 1.5 V
Since the capacitor is initially uncharged, the capacitive reactance is zero.
From ohms law;
Voltage across the circuit is directly proportional to the opposition to the flow of current.
In these circumstances, as the battery only "sees"a resistor, the initial current can be found applying Ohm's law to the resistor, as follows:
[tex]V = I_{0}*R \\\\ I_{0} = \frac{V}{R} = \frac{1.50V}{8.011e3\Omega}\\ = 0.0187 mA[/tex]
The initial current (that will be diminishing as the capacitor charges), is 0.0187 mA.
An RLC circuit with a resistor of R\:=\:1 R = 1 k, capacitor ofC\:=\:3 C = 3 F, and inductor ofL\:=\:2 L = 2 H reaches a maximum current through the inductor of 7 mA. When all of the energy stored in the circuit is in the inductor, what is the magnetic energy stored? (Express your answer in micro-Joules) In the same circuit explained above, if all the energy is then transferred into the capacitor, what voltage drop will there be across the capacitor? (Express your answer in Volts to the hundredths place)
Answer:
Magnetic energy stored in the inductor when all of the energy in the circuit is in the inductor = 0.049 mJ
If all the energy is then transferred into the capacitor, the voltage drop across the capacitor = 0.00572 V = 0.01 V (expressed to the hundredths value)
Explanation:
In an RLC circuit with maximum current of 7mA = 0.007 A
When all of the energy is stored in the inductor, maximum current will flow through it,
Hence E = (1/2) LI²
L = inductance of the inductor = 2 H
E = (1/2) (2)(0.007²) = 0.000049 J = 0.049 mJ
When all the energy in the circuit is in the capacitor, this energy will be equal to the energy calculated above.
And for a capacitor, energy is given as
E = (1/2) CV²
E = 0.000049 J, C = 3 F, V = ?
0.000049 = (1/2)(3)(V²)
V = 0.00572 V = 0.01 V
What is the magnitude of the electric field at a distance 60 cm from the center of the sphere? The radius of the sphere 30 cm, the charge on the sphere is 1.56 × 10−5 C and the permittivity of a vacuum is 8.8542 × 10−12 C 2 /N · m2 . Answer in units of N/C.
Answer
[tex]3.9*10^{5}N/C[/tex]
Explanation:
from the expression for determing the magnetic field strength
[tex]E=\frac{q}{4\pi e_{0}d^2 }\\[/tex]
since the charge is given as
[tex]q=1.56*10^{-5}c\\[/tex]
and the distance is
d=60cm=0.6m
We can calculate the constant k
[tex]K=\frac{1}{4\pi e_{0}}\\ K=\frac{1}{4\pi *8.8542*10^{-12}}\\k=8.98*10^{9}\\[/tex]
if we substitute values, we arrive at
[tex]E=\frac{8.98*10^9 *1.56*10^{-5}}{0.6^2} \\E=389133.33\\E=3.9*10^{5}N/C[/tex]
Explanation:
Below is an attachment containing the solution.
Reasons for which petroleum is the chosen fuel for transportation in the U.S. include
1) its energy value per unit volume
2) its ability to quickly start or stop providing energy
3) its low amount of pollution produced per joule
Answer:
The Reasons for which petroleum is the chosen fuel for transportation in the U.S. include number 1) and 2).
Explanation:
The main reasons why oil is the most used fuel in the USA is because of its energy potential with a high combustion power and a better octane rating compared to other fuels. Thus, fossil fuel derived from oil has a high energy value per unit volume and an ability to quickly start or stop providing energy.
A 20.0-kg block is initially at rest on a horizontal surface. A horizontal force of 77.0 N is required to set the block in motion, after which a horizontal force of 56.0 N is required to keep the block moving with constant speed.Find the coefficients of static and kinetic friction from this information.
Answer: The coefficient of static friction is 3.85 and The coefficient of kinetic friction is 2.8
Explanation:
in the attachment