The speed of transverse waves on the steel piano wire can be calculated using the formula √(Tension / (Mass per unit length)). To reduce the wave speed by a factor of 2 without changing the tension, we can solve for the new wave speed, and then calculate the difference in mass per unit length with the copper wire.
Explanation:The speed of transverse waves on a steel piano wire can be calculated using the formula:
Speed = √(Tension / (Mass per unit length))
Where the tension in the wire is 500 N and the mass per unit length is calculated by dividing the mass of the wire by its length. Therefore, the mass per unit length is 5 g / 0.7 m = 7.14 g/m.
To reduce the wave speed by a factor of 2 without changing the tension, we can use the equation:
New wave speed = √(New tension / (Mass per unit length))
We can solve this equation for the new tension by rearranging it as:
New tension = (New wave speed)^2 * (Mass per unit length)
Since we want to reduce the wave speed by a factor of 2, the new wave speed is half the original speed. Substituting these values into the equation, we have:
(0.5 * Old wave speed)^2 * (Mass per unit length) = 500 N
Solving for the new mass per unit length gives:
New mass per unit length = 500 N / (0.5 * Old wave speed)^2
The difference between the new mass per unit length and the mass per unit length of copper wire is the mass of copper wire that needs to be wrapped around the steel wire. However, we would need additional information to calculate this difference.
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In a World Cup soccer match, Juan is running due north toward the goal with a speed of 8.00 m/s relative to the ground. A teammate passes the ball to him. The ball has a speed of 12.0 m/s and is moving in a direction 37.0o east of north, relative to the ground. What are the magnitude and direction of the ball’s velocity relative to Juan?
Answer:
19m/s
22.3 degrees
Explanation:
it is a case aof relative velocity.
the basic for relative velocity vector equation is :
V_b = V_j + V_(b/j)---------------1
V_b: ball velocity relative to ground
V_j : Jaun velocity relative to ground
V_(b/j): ball velocity relative to jaun
reference frame:
We take east and north as +ve x and +ve y
V_(b/j) = V_b - V_j
so for x-axis;
net x-component of V_(b/j) = 12 sin (37) + 0 = 7.22m/s
net y-component of V_(b/j) = 12 cos (37) + 8 = 17.6m/s
magnitude = ((7.22^2)+(17.6^2))^(0.5) = 19 m/s
*direction with respect to Jaun = angle between the vertical (North) and vector V_(b/j)
angle = arctan(7.22/17.6) = 22.3 degrees
A ball is launched vertically with an initial speed of y˙0= 50 m/s, and its acceleration is governed by y¨=-g-cDy˙2, where the air drag coefficient cD is given by cD= 0.001 m-1. What is the maximum height that the ball reaches? Compare this to the maximum height achieved when air drag is neglected.
Answer:
Explanation:
Given
acceleration is given by
[tex]a=-g-c_Dv^2[/tex]
where [tex]\ddot{y}=a[/tex]
[tex]\dot{y}=v[/tex]
Also acceleration is given by
[tex]a=v\frac{\mathrm{d} v}{\mathrm{d} s}[/tex]
[tex]ds=\frac{v}{a}dv[/tex]
[tex]\int ds=\int \frac{v}{-g-0.001v^2}dv[/tex]
[tex]\Rightarrow Let -g-0.001v^2=t[/tex]
[tex]-0.001\times 2vdv=dt[/tex]
[tex]vdv=-\frac{dt}{0.002}[/tex]
[tex]at\ v_0=50\ m/s,\ t=-g-0.001(50)^2[/tex]
[tex]t=-g-2.5[/tex]
at [tex]v=0,\ t=-g[/tex]
[tex]\int_{0}^{s}ds=\int_{-g}^{-g-2.5}\frac{-dt}{0.002t}[/tex]
[tex]\int_{0}^{s}ds=\int^{-g}_{-g-2.5}\frac{dt}{0.002t}[/tex]
[tex]s=\frac{1}{0.002}lnt|_{-g}^{-g-2.5}[/tex]
[tex]s=\frac{1}{0.002}\ln (\frac{g+2.5}{g})[/tex]
[tex]s=113.608\ m[/tex]
when air drag is neglected maximum height reached is
[tex]h=\frac{v_0^2}{2g}[/tex]
[tex]h=\frac{50^2}{2\times 9.8}[/tex]
[tex]h=127.55\ m[/tex]
A stiff wire bent into a semicircle of radius a is rotated with a frequency f in a uniform magnetic field, as suggested in Fig. 34-51. What are (a) the frequency and (b) the amplitude of the emf induced in the loop
The frequency of the loop is 58 Hz and the amplitude of the emf induced in the loop is 7.73 mV and this can be determined by using the given data.
Given :
A stiff wire bent into a semicircle of radius 'a' is rotated with a frequency f in a uniform magnetic field.
According to the data, the angular speed is 58 rev/sec that is, 364.4 rad/sec, the magnetic field is 15 mT that is, 15 [tex]\times[/tex] [tex]10^{-3}[/tex] T, and the radius 'a' is 3 cm that is, 3 [tex]\times[/tex] [tex]10^{-2}[/tex] m.
a) The frequency is 58 rev/sec that is 58 Hz.
b) The amplitude of the emf induced in the loop can be calculated as:
[tex]\rm \epsilon = \dfrac{\omega B \pi a^2}{2}[/tex]
Now, substitute the values of the known terms in the above formula.
[tex]\epsilon = \dfrac{364.4\times 15\times10^{-3}\times \pi \times (3\times 10^{-2})^2}{2}[/tex]
Further, simplify the above expression.
[tex]\rm \epsilon = 0.007728\;V[/tex]
[tex]\rm \epsilon = 7.73\;mV[/tex]
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Write this large number in scientific notation. Determine the values of Vm) and (n) when the following mass of the Earth is written in scientific notation: 5,970,000,000,000,000,000,000,000 (rm kgl) Enter I(ml) and (nl), separated by commas.
Answer : The answer is, 5.97, 24
Explanation :
Scientific notation : It is the representation of expressing the numbers that are too big or too small and are represented in the decimal form with one digit before the decimal point times 10 raise to the power.
For example :
5000 is written as [tex]5.0\times 10^3[/tex]
889.9 is written as [tex]8.899\times 10^{-2}[/tex]
In this examples, 5000 and 889.9 are written in the standard notation and [tex]5.0\times 10^3[/tex] and [tex]8.899\times 10^{-2}[/tex] are written in the scientific notation.
If the decimal is shifting to right side, the power of 10 is negative and if the decimal is shifting to left side, the power of 10 is positive.
As we are given the 5,970,000,000,000,000,000,000,000 in standard notation.
Now converting this into scientific notation, we get:
[tex]\Rightarrow 5,970,000,000,000,000,000,000,000=5.97\times 10^{24}[/tex]
As, the decimal point is shifting to left side, thus the power of 10 is positive.
Hence, the answer is, [tex]5.97\times 10^{24}[/tex]
Now the answer is comparing to [tex]m.\times 10^n[/tex]
So, m = 5.97 and n = 24
Thus, the answer is, 5.97, 24
A flat sheet with an area of 3.8 m 2 is placed in a uniform electric field of magnitude 10 N/C. The electric flux through the sheet is 6.0 Nm 2 /C . What is the angle (in degrees) between the electric field and sheet's normal vector?
Answer:
The angle between the electric field and sheet's normal vector is 80.96 degrees.
Explanation:
Given that,
Area of the flat sheet, [tex]A=3.8\ m^2[/tex]
Electric field, E = 10 N/C
Electric flux of the sheet, [tex]\phi=6\ Nm^2/C[/tex]
The electric flux is through the sheet is given by the dot product of electric field and the area vector. It is given by :
[tex]\phi=E{\cdot} A[/tex]
or
[tex]\phi=EA\ cos\theta[/tex]
[tex]\theta[/tex] is the angle between electric field and sheet's normal vector
So,
[tex]cos\theta=\dfrac{\phi}{EA}[/tex]
[tex]cos\theta=\dfrac{6}{10\times 3.8}[/tex]
[tex]\theta=cos^{-1}(0.157)[/tex]
[tex]\theta=80.96^{\circ}[/tex]
So, the angle between the electric field and sheet's normal vector is 80.96 degrees. Hence, this is the required solution.
Final answer:
The angle between the electric field and the flat sheet's normal vector, given the electric flux of 6.0 Nm²/C and field magnitude of 10 N/C, is approximately 81.2 degrees.
Explanation:
The question involves calculating the angle between an electric field and a flat sheet's normal vector, given the electric flux and the field magnitude. The formula for electric flux (Φ) is given by Φ = E * A * cos(θ), where E is the electric field strength, A is the area through which the field lines pass, and θ is the angle between the field and the normal to the surface. In this case, we have the electric flux (Φ = 6.0 Nm²/C), the electric field (E = 10 N/C), and the area (A = 3.8 m²). To find the angle θ, we rearrange the equation to solve for the cosine of the angle: cos(θ) = Φ / (E * A).
Substituting the given values, we get cos(θ) = 6.0 / (10 * 3.8), which simplifies to cos(θ) = 0.1579. Taking the arccosine of both sides, we find θ ≈ arccos(0.1579). By calculating this, we find that θ ≈ 81.2°.
Thus, the angle between the electric field and the sheet's normal vector is approximately 81.2 degrees.
A sample of N2O gas has a density of 2.697 g/L at 298 K. What must be the pressure of the gas (in mmHg)?
Answer:
[tex]P=1139.16384mmHg[/tex]
Explanation:
Given data
[tex]R=0.08206(\frac{L.Atm}{mol.K} )\\Density=2.697g/L\\Temperature=298K\\f.wt=44(g/mol)\\[/tex]
To find
Pressure
Solution
From Ideal gas law we know that
[tex]PV=nRT\\P=(nR\frac{T}{V} )=(R(\frac{mass}{f.wt} )(\frac{T}{V} ))\\P=R(\frac{mass}{volume}) (\frac{T}{f.wt} )=R(Density)(\frac{T}{f.wt} )[/tex]
Substitute the given values to find pressure
So
[tex]P=(0.08206\frac{L.Atm}{mol.K} )(2.697g/L)(298K)(44g/mol)^{-1}\\ P=1.4989Atm\\[/tex]
Convert Atm to mmHg
Multiply the pressure values by 760
So
[tex]P=1139.16384mmHg[/tex]
An object is moving along the x-axis. At t = 0 it has velocity v0x = 20.0 m/s. Starting at time t = 0 it has acceleration ax = - Ct, where C has units of m/s3. (a) What is the value of C if the object stops in 8.00 s after t = 0? (b) For the value of C calculated in part (a), how far does the object travel during the 8.00 s?
The value of C if the object stops in 8.00 s is 0.625 m/s³.
The distance traveled by the object before stopping in 8 seconds is 40 m.
The given parameters;
initial velocity, [tex]v_0[/tex] = 20.0 m/sinitial time of motion, t = 0acceleration of the object, a = -CtThe value of C is determined by using velocity equation as shown below;
[tex]\frac{dv}{dt} = -Ct\\\\dv = -Ctdt\\\\\int\limits^v_{v_0} \, dv = -\int\limits^t_{t_0} \, Ct \\\\v-v_0= -C[\frac{t^2}{2} ]^t_0\\\\v-v_0 = - \frac{1}{2} Ct^2\\\\0 - 20 = - \frac{1}{2}C(8)^2\\\\-20 = -32 C\\\\C = \frac{20}{32} = 0.625 \ m/s^3[/tex]
The acceleration of the object during 8 seconds is calculated as follows;
a = -Ct
a = -0.625(8)
a = -5 m/s²
The distance traveled by the object before stopping in 8 seconds is calculated as follows;
[tex]v^2 = u^2 + 2as\\\\0 = 20^2 + 2(-5)s\\\\0 = 400 - 10s\\\\10s = 400 \\\\s = \frac{400}{10} \\\\s = 40 \ m[/tex]
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A value of C that stops the object in 8 seconds is 1.25 m/s³. The object travels a total distance of 53.33 meters during this time.
An object is moving along the x-axis with an initial velocity of v₀x = 20.0 m/s and an acceleration of ax = -Ct where C is in m/s³. We'll solve for the value of C and the distance traveled in 8.00 s.
Part (a): Finding the value of C
To determine the value of C, consider the velocity function:
v(t) = v₀x + ∫ax dt = v₀x + ∫-Ct dt
Integrating the acceleration to get the velocity:
v(t) = 20.0 m/s - (C/2)t²
Given that the object stops at t = 8.00 s, set v(8.00) = 0:
0 = 20.0 m/s - (C/2)(8.00 s)²
Solving for C:
20.0 m/s = C × 32 s²
C = 40/32 = 1.25 m/s³
Part (b): Distance traveled in 8.00 s
The displacement function x(t) can be found by integrating the velocity function:
x(t) = ∫v(t) dt
x(t) = ∫[20.0 m/s - (C/2)t²] dt
x(t) = 20.0t - (C/6)t³
Using C = 1.25 m/s³ and t = 8.00 s:
x(8.00) = 20.0(8.00) - (1.25/6)(8.00)³
x(8.00) = 160.0 - (1.25/6)(512)
x(8.00) = 160.0 - 106.67
x(8.00) = 53.33 m
A projectile thrown from a point P moves in such a way that its distance from P is always increasing. Find the maximum angle above the horizontal with which the projectile could have been thrown. Ignore air resistance.
Answer
70.52°
Explanation
The distance between projectile's position and it's starting point at any time is given by the relation
r² = x² + y²
where x = horizontal distance covered and y = vertical distance covered
According to projectile motion the horizontal displacement is given by
x = v(x)t = v cos(θ) t
Also the vertical component is given by
y = v(y) t - 0.5gt² = v sin(θ) t - 0.5gt²
Substituting the x and y values into the r-equation yields,
r² = (v cos(θ) t)² + (v sin(θ) t - 0.5gt²)²
r² = v²(cos²(θ))t² + v²(sin²(θ))t² – (vg sin(θ))t³+ 0.25 g²(t^4)
r² = v²t² (cos²(θ)+ sin²(θ)) – (vg sin(θ))t³ + 0.25 g²(t^4)
r² = v²t² – (vg sin(θ))t³ + 0.25 g²(t^4)
Differentiate r with respect to t
r(dr/dt) = 2v²t - 3vg sin(θ)t² + g²t³
At maximum angle the projectile could have been thrown above the horizontal, dr/dt = 0
2v²t - 3vg sin(θ)t² + g²t³ = 0
Divide through by t
2v² - 3vg sin(θ)t + g²t² = 0
g²t² - 3vg sin(θ)t + 2v² = 0
This can be solved using the general law for quadratic equations
(-b ± √(b² - 4ac))2a
a = g², b = -3vg sin(θ) c = 2v²
t = ((3vg sin(θ)) ± √(9v²g²sin²(θ) - 8g²v²))/2g²
This equation makes sense when the value under the square root is positive, that is, the square root exists.
9v²g²sin²(θ) - 8g²v² > 0
9sin²(θ) - 8 > 0
Meaning sin²(θ) = 8/9
Sin θ = (2√2)/3
θ = 70.52°
QED!!!
You throw a baseball straight up in the air so that it rises to a maximum height much greater than your height. Is the magnitude of the ball’s acceleration greater while it is being thrown or after it leaves your hand? Explain.
The ball's acceleration is constant in magnitude and direction, from the instant it leaves your hand, until the instant it hits the ground, no matter what direction or speed you throw it.
It's the acceleration of gravity, on whatever planet you happen to be standing when you throw the ball.
Final answer:
The baseball's magnitude of acceleration is greater while being thrown than after it leaves the hand due to the additional force applied by the thrower, while in free fall, the ball is subject only to gravity. With air resistance, the ball takes longer to go up than to come back down.
Explanation:
The question pertains to the acceleration of a baseball when thrown straight up into the air. While being thrown, the ball experiences an acceleration greater than the acceleration due to gravity because of the force applied by the person's arm. After the ball leaves the hand, however, the only force acting on it is the force of gravity, which gives it a constant acceleration of approximately 9.81 m/s² downward, regardless of air resistance. In the absence of other forces, the magnitude of acceleration when the ball is in free fall is less than the acceleration imparted to the ball by the thrower's arm.
When air resistance is considered, it acts to slow down the ball as it rises and speeds up as it falls. Therefore, with air resistance, the time it takes for the ball to go up is greater than the time it takes to come back down, because air resistance removes kinetic energy from the ball on the way up, slowing it down more quickly than gravity alone would.
A bimetallic strip consists of two 1-mm thick pieces of brass and steel bonded together. At 20C, the strip is completely straight and has a length of 10 cm. At 30C, the strip bends into a circular arc. What is the radius of curvature of this arc?
Answer:
R = 16.67 m
Explanation:
Given:
- Initial Temperature T_i = 20 C
- Thickness of both strips t = 0.001 m
- Final Temperature T_f = 30 C
- Length of the strip L = 0.1 m
- coefficient of linear expansion for brass a_b = 19*10^-6
- coefficient of linear expansion for steel a_s = 13*10^-6
Find:
What is the radius of curvature of this arc R?
Solution:
- The radius of curvature R in relation to dT and a_b, a_s:
R = t / dT*(a_b - a_s)
R = 0.001 / (30-20)*(19-13)*10^-6
R = 16.67 m
As an astronaut visiting the Planet X, you're assigned to measure the free-fall acceleration. Getting out your meter stick and stop watch, you time the fall of a heavy ball from several heights. Your data are as follows:Height (m) Fall Time (s)0 01 0.542 0.723 0.914 1.015 1.17a. Analyze these data to determine the free-fall acceleration on Planet X.b. Determine the uncertainty in the free-fall acceleration.
Answer:
[tex]g \approx 7.4 m/s^2[/tex]
Explanation:
Assuming the following data:
Heigth (m): 0 , 1, 2, 3, 4, 5
Time (s): 0.00, 0.54,0.73, 0.91, 1.01, 1.17
We know from kinematics that the height is given by the following expression:
[tex] h_f = h_i + v_i t + \frac{1}{2} g t^2[/tex]
Assuming for this case that the initial velocity is [tex]v_i[/tex] we can find a polynomial with degree 2 in order to have an estimation for the height with the time.
We can use excel for this and we can see the polynomial adjusted for the data given.
As we can see the best polynomial of degree 2 is given by:
[tex] h(x)= -0.0178 +0.066 x+ 3.6801 x^2[/tex]
For our case x = time and we can rewrite the expression like this
[tex] h(t)= -0.0178 +0.066 t+ 3.6801 t^2[/tex]
And if we are interested on the gravity we want on special the last term of this equation, we can set equal the following terms:
[tex] 3.6801 t^2 = \frac{1}{2} g t^2[/tex]
And solving for g we got:
[tex] 2*3.6801 = g= 7.36 \frac{m}{s^2}[/tex]
So then a good approximation for the gravity of the planet rounded to 2 significant figures is 7.4 m/s^2
To determine the free-fall acceleration on Planet X, you can use the formula: acceleration = 2 * height / fall time^2. Calculating the acceleration for each data point, and the uncertainty can be determined by finding the range of values.
Explanation:a.
To determine the free-fall acceleration on Planet X, we can use the formula: acceleration = 2 * height / fall time^2. We can calculate the acceleration using the given data:
For height 1m, fall time 0.54s, the acceleration is 7.485 m/s^2
For height 2m, fall time 0.72s, the acceleration is 8.660 m/s^2
For height 3m, fall time 0.91s, the acceleration is 9.337 m/s^2
For height 4m, fall time 1.01s, the acceleration is 9.704 m/s^2
For height 5m, fall time 1.17s, the acceleration is 9.335 m/s^2
b.
To determine the uncertainty in the free-fall acceleration, we can calculate the range of values by subtracting the smallest acceleration from the largest acceleration. The smallest acceleration is 7.485 m/s^2 and the largest acceleration is 9.704 m/s^2. Therefore, the uncertainty in the free-fall acceleration is 2.219 m/s^2.
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A raw egg can be dropped from a third-fl oor window and land on a foam-rubber pad on the ground without breaking. If a 75.0-g egg is dropped from a window located 32.0 m above the ground and a foam-rubber pad that is 15.0 cm thick stops the egg in 9.20 ms, (a) by how much is the pad compressed?(b) What is the average force exertedon the egg after it strikes the pad?
Answer:
N 204.13
Explanation:
Using equation of motion
v² = u² + 2as
u = 0 is the egg was dropped from rest.
v = 2 × 9.8 × 32 = √627.2 = 25.04 m/s
when the egg hit the foam-rubber, the acceleration can be calculated with
a = change in velocity / change in time = - 25.04 / 0.0092 = -2721.74 m/s²
a) how much it is compressed
v² = u² + 2as
- u² = 2 (-2717.4) s
- 627.2 / -5443.48 = s
s = 0.1152 m = 11.52 cm
b) average force exerted on the egg = mΔv / Δt = 25.04 × 0.075 / 0.0092 = 204.13
Calculate the electric field (in V/m) between two parallel plates connected to a 45 V battery if the plates are separated by a) 3 cm and b) 5cm. What is the resulting force on an electron in each of these fields?
Answer:
Explanation:
Given
Voltage of battery [tex]V=45\ V[/tex]
electric field(E) is given by
[tex]E=|-\frac{dV}{dx}|[/tex]
i.e. Change in Potential over a distance x
(a)When Plate are separated by 3 cm apart
[tex]E=|\frac{45}{3\times 10^{-2}}|[/tex]
[tex]E=1500\ V/m[/tex]
(b)When Plates are 5 cm apart
[tex]E=|-\frac{45}{5\times 10^{-2}}|[/tex]
[tex]E=900\ V/m[/tex]
Force on electron is given by
[tex]F=charge\times Electric\ Field[/tex]
[tex]F=q\times E[/tex]
For case a
[tex]F=1.6\times 10^{-19}\times 1500[/tex]
[tex]F=24\times 10^{-17}\ N[/tex]
(b)[tex]F=1.6\times 10^{-19}\times 900=14.4\times 10^{-17}\ N[/tex]
A submarine periscope uses two totally reflecting 45-45-90 prisms with total internal reflection on the sides adjacent to the 45 degree angles. Explain why the periscope will no longer work if it springs a leak and the bottom prism is covered with water. Note: The index of refraction for water is 1.33. The index of refraction for glass is 1.52
Answer
Given,
Periscope uses 45-45-90 prisms with total internal reflection adjacent to 45°.
refractive index of water, n_a = 1.33
refractive index of glass, n_g = 1.52
When the light enters the water, water will act as a lens and when we see the object from the periscope the object shown is farther than the usual distance.
Calculate the number of atoms contained in a cylinder (1 m radiusand1 m deep)of (a) magnesium (b) lead.
Answer:
The question is incomplete,below is the complete question
"Calculate the number of atoms contained in a cylinder (1μm radius and 1μm deep)of (a) magnesium (b) lead."
Answer:
a. 1.35*10^{11} atoms
b. 1.03*10^{11} atoms
Explanation:
First, we determine the volume of the magnesium in the cylinder container
using the volume of a cylinder
[tex]V=\pi r^{2}h\\ r=10^{-6}m\\ h=10^{-6}m\\V=\pi *10^{-6*2}*10^{-6}\\V=\pi *10^{-18}\\V=3.14*10^{-18}m^{3}\\[/tex]
a. Next we determine the mass of the magnesium ,
using the density=mass/volume
since density of a magnesium
[tex]the density of magnesium =1.738*10^{3}kg/m^{3} \\mass=density * volume \\mass=1.738*10^{3}*3.14*10^{-18}\\mass=5.46*10^{-15}kg\\ \\mass=5.46*10^{-12}g\\[/tex]
Finally to calculate the number of atoms,
we determine the number of moles
mole=mass/molarmass
[tex]mole=5.46*10^{-12}/ 24.305\\mole=0.225*10^{-12}mol\\[/tex]
Hence the number of atoms is
number of atoms=mole*Avogadro's constant
[tex]number of atoms = 0.225*10^{-12}*6.02*10^{23}\\number of atoms =1.35*10^{11} atoms[/tex]
b. for he lead, we determine the mass of the lead ,
using the density=mass/volume
since density of a magnesium
[tex]the density of lead =11.34*10^{3}kg/m^{3} \\mass=density * volume \\mass=11.34*10^{3}*3.14*10^{-18}\\mass=35.60*10^{-15}kg\\ \\mass=35.60*10^{-12}g\\[/tex]
Finally to calculate the number of atoms,
we determine the number of moles
mole=mass/molarmass
[tex]mole=35.60*10^{-12}/ 207.2\\mole=0.1718*10^{-12}mol\\[/tex]
Hence the number of atoms is
number of atoms=mole*Avogadro's constant
[tex]number of atoms = 0.1718*10^{-12}*6.02*10^{23}\\number of atoms =1.03*10^{11} atoms[/tex]
A helicopter is hovering above the ground. Jim reaches out of the copter (with a safety harness on) at 180 m above the ground. A package is launched upward, from a point on a roof 10 m above the ground. The initial velocity of the package is 50.5 m/s. Consider all quantities as positive in the upward direction. Does Jim Bond have a chance to catch the package? (calculate how high will it go)
Answer:
The maximum height of the package is 140 m above the ground. Jim Bond will not catch the package.
Explanation:
Hi there!
The equation of height and velocity of the package are the following:
h = h0 + v0 · t + 1/2 · g · t²
v = v0 + g · t
Where:
h = height of the package at time t.
h0 = initial height.
v0 = initial velocity.
t = time.
g = acceleration due to gravity (-9.81 m/s² because we consider the upward direction as positive).
v = velocity of the package at a time t.
First, let´s find the time it takes the package to reach the maximum height. For this, we will use the equation of velocity because we know that at the maximum height, the velocity of the package is zero. So, we have to find the time at which v = 0:
v = v0 + g · t
0 = 50.5 m/s - 9.8 m/s² · t
Solving for t:
-50.5 m/s / -9.81 m/s² = t
t = 5.15 s
Now, let´s find the height that the package reaches in that time using the equation of height. Let´s place the origin of the frame of reference on the ground so that the initial position of the package is 10 m above the ground:
h = h0 + v0 · t + 1/2 · g · t²
h = 10 m + 50.5 m/s · 5.15 s - 1/2 · 9.81 m/s² · (5.15 s)²
h = 140 m
The maximum height of the package is 140 m above the ground. Jim Bond will not catch the package.
Janet wants to find the spring constant of a given spring, so she hangs the spring vertically and attaches a 0.46 kg mass to the spring’s other end. The acceleration of gravity is 9.81 m/s 2 . If the spring stretches 3.7 cm from its equilibrium position, what is the spring constant?
Answer: The value of spring constant is 121.9 N/m
Explanation:
Force is defined as the mass multiplied by the acceleration of the object.
[tex]F=m\times g[/tex]
where,
F = force exerted on the object = ?
m = mass of the object = 0.46 kg
g = acceleration due to gravity = [tex]9.81m/s^2[/tex]
Putting values in above equation, we get:
[tex]F=0.46kg\times 9.81m/s^2=4.51N[/tex]
To calculate the spring constant, we use the equation:
[tex]F=k\times x[/tex]
where,
F = force exerted on the spring = 4.51 N
k = spring constant = ?
x = length of the spring = 3.7 cm = 0.037 m (Conversion factor: 1 m = 100 cm)
Putting values in above equation, we get:
[tex]4.51N=k\times 0.037m\\\\k=\frac{4.51N}{0.037m}=121.9N/m[/tex]
Hence, the value of spring constant is 121.9 N/m
You are on the west bank of a river that is flowing north with a speed of 1.2 m/s. Your swimming speed relative to the water is 1.5 m/s, and the river is 60 m wide. What is your path relative to the earth that allows you to cross the river in the shortest time? Explain your reasoning.
Answer:
head straight across the river (perpendicular to the bank).
Explanation:
To cross the river in the shortest time first your velocity should be relative to the earth has to have the largest possible component to the bank
suppose,
S be the swimmer
E be the earth
W be the water
[tex]u_{x/y}[/tex] be the velocity of X relative to Y
resultant velocity relative to E will be:
[tex]u_{S/E}=u_{S/W}+u_{W/E}[/tex]
[tex]u_{W/E}[/tex] is parallel to the bank so,
[tex]u_{S/E}[/tex] has its largest component perpendicular to the bank when [tex]u_{S/W}[/tex] is in that direction
so to cross the river in the shortest time you should straight across the current will then carry you downstream so your path relative to the earth is directed at angle downstream
Final answer:
To cross the river in the shortest time, you must swim perpendicularly to the current. In this case, swimming directly eastward with a speed of 1.5 m/s across a 60 m wide river flowing north at 1.2 m/s will take you across in 40 seconds without being carried downstream.
Explanation:
To cross the river in the shortest time, you must aim to minimize the time spent fighting the water current. The key is to swim in a direction such that your velocity relative to the water combines with the river's velocity to give a resultant path straight across the river. Since the river is flowing north with a speed of 1.2 m/s and your swimming speed relative to the water is 1.5 m/s, the shortest path across would be due east.
If you swim directly eastward, your swimming speed relative to the water ensures that you are moving across the river without being pushed downstream. Thus, the only velocity affecting your eastward crossing is your swimming speed, which is perpendicular to the current. Since the water's current is orthogonal to your motion, it does not affect the time it takes to cross. You'll cross the 60 m wide river in the shortest amount of time by moving at your maximum speed of 1.5 m/s directed perpendicularly to the current.
Considering a swimmer in the given scenario, here's an example to illustrate this concept with numbers:
Width of river: 60 mSpeed of swimmer relative to water: 1.5 m/sSpeed of river current: 1.2 m/sTime to cross = Width of river / Speed of swimmer relative to the water = 60 m / 1.5 m/s = 40 secondsTherefore, the time taken to cross the river is 40 seconds, and the path taken by the swimmer is perpendicular to the flow of the river, relative to the Earth.
Does the KE of a car change more when it accelerates from 23 km/h to 33 km/h or when it accelerates from 33 km/h to 43 km/h?
a. From 23 km/h to 33 km/h
b. From 33 km/h to 43 km/h
c. More information is needed.
Answer:
b. From 33 km/h to 43 km/h
Explanation:
Lets take mass of the car = m
We know that The change kinetic energy KE is give as
[tex]KE=\dfrac{1}{2}m(v^2-u^2)[/tex]
When speed changes from 23 km/h to 33 km/h :
We know that 1 km/h= 0.27 m/s
[tex]KE=\dfrac{1}{2}m(v^2-u^2)[/tex]
[tex]KE=\dfrac{1}{2}\times m((0.27\times 33)^2-(0.27\times 23)^2)[/tex]
KE= 20.412m J
When speed changes from 33 km/h to 43 km/h :
We know that 1 km/h= 0.27 m/s
[tex]KE=\dfrac{1}{2}m(v^2-u^2)[/tex]
[tex]KE=\dfrac{1}{2}\times m((0.27\times 43)^2-(0.27\times 33)^2)[/tex]
KE= 27.702m J
Therefore we can say that when speed changes 33 km/h to 43 km/h ,the kinetic energy will changes more.
The inner planets formed:
a. by collisions and mergers of planetesimals.
b. in the outer solar system and then were deflected inward by interactions with Jupiter and Saturn.
c. when the Sun's heat destroyed all the smaller bodies in the inner solar system.
d. when a larger planet broke into pieces.
Answer:
a. by collisions and mergers of planetesimals.
Explanation:
Inner planets are planets within 1.5 AU distance from the sun. These are called terrestrial planets because they are somewhat similar to Earth, mainly made of rocks.
The main ingredient of these planets are solar nebula and interstellar dust condensation of which leads to formation of small rock particles. These particles come close to each other under in the influence of gravity and other forces. As the mass of the particles increase they form planetesimals, these planetesimals eventually merge to form planets.
A skydiver jumps out of an airplane. Her speed steadily increases until she deploys her parachute, at which point her speed quickly decreases. She subsequently falls to earth at a constant rate, stopping when she lands on the ground.
The question is incomplete but an analysis of the situation using various useful physics concepts can still be made
Answer:
When she immediately jumps out of the plane, the downward force(weight) is greater than any opposing forces upwards (such as air resistance). So the netforce is downwards and therefore the direction of acceleration is also downwards. The direction of acceleration is always in the direction of the netforce The person is not falling at the rate of free fall (9.8 m/s²) because that is for bodies falling in a vacuum and this person is not, air resistance is very much a factor hereUpon deployment of the parachute, upward forces (air resistance) increases matching the downward forces in size, causing the netforce to be zero. A zero netfroce means zero acceleration which is why the person stops accelerating and falls at a constant rateA piece of clay sits 0.10 m from the center of a potter’s wheel. If the potter spins the wheel at an angular speed of 15.5 rad/s, what is the magnitude of the centripetal acceleration of the piece of clay on the wheel?
Answer:
[tex]a=24.025\ m/s^2[/tex]
Explanation:
Given that
Distance from the center ,r= 0.1 m
The angular speed ,ω = 15.5 rad/s
We know that centripetal acceleration is given as
a=ω² r
a=Acceleration
r=Radius
ω=angular speed
a=ω² r
Now by putting the values in the above equation we get
[tex]a=15.5^2\times 0.1\ m/s^2[/tex]
[tex]a=24.025\ m/s^2[/tex]
Therefore the acceleration of the clay will be [tex]a=24.025\ m/s^2[/tex].
A man stands on the roof of a building of height 14.0 m and throws a rock with a velocity of magnitude 26.0 m/s at an angle of 28.0 ∘ above the horizontal. You can ignore air resistance.
The question involves analyzing the projectile motion of a rock thrown from a building using physics principles like motion decomposition and energy conservation. It requires breaking down the initial velocity into horizontal and vertical components and applying kinematic equations to determine parameters such as max height, range, and flight time.
Explanation:This question involves the principles of projectile motion and energy conservation in physics. When the man throws the rock at an angle of 28 degrees above the horizontal with an initial velocity of 26.0 m/s from a height of 14.0 meters, we need to analyze the horizontal and vertical components of the motion separately to determine various aspects of the rock's trajectory, such as its range, maximum height, and time of flight. However, since the specific request is missing in this context, we'll focus on the general approach to solving such problems.
To solve problems involving objects thrown at an angle, we first decompose the initial velocity into its horizontal (vx = v*cos(θ)) and vertical (vy = v*sin(θ)) components, where v is the magnitude of the initial velocity and θ is the angle of projection. The horizontal motion is uniform, meaning the velocity remains constant, whereas the vertical motion is affected by gravity, leading to acceleration in the opposite direction of the initial vertical velocity component.
Energy conservation or kinematic equations can be used to find specific details like maximum height reached, time of flight, and range. For example, the formula s = ut + 0.5at² can be applied where s is displacement, u is initial velocity, a is acceleration (gravity in the case of vertical motion), and t is time. Remember, acceleration due to gravity (a) is -9.8 m/s², indicating it acts downwards. Ignoring air resistance simplifies calculations by omitting drag force considerations.
The maximum horizontal distance is approximately 61.7 meters. This is determined using the projectile motion equations for horizontal distance with initial velocity, angle, and height given.
To find the maximum horizontal distance the rock travels, we can analyze the projectile motion. The initial velocity of 26.0 m/s is broken down into horizontal and vertical components. The horizontal component is [tex]\( v_x = v \cdot \cos(\theta) \)[/tex], where \( v \) is the magnitude of the velocity (26.0 m/s) and \( \theta \) is the angle (28.0 degrees). The vertical component is [tex]\( v_y = v \cdot \sin(\theta) \).[/tex]
The vertical motion is affected by gravity, and the time it takes for the rock to hit the ground can be calculated using the equation [tex]\( h = v_y \cdot t - \frac{1}{2} g t^2 \),[/tex] where \( h \) is the initial height (14.0 m), \( g \) is the acceleration due to gravity (approximately 9.8 m/s\(^2\)), and \( t \) is the time of flight.
Using the quadratic formula to solve for \( t \), we find two solutions: one when the rock is at the initial height and one when it hits the ground. We use the positive solution for the time of flight to calculate the horizontal distance traveled using the equation [tex]\( d = v_x \cdot t \).[/tex]
Substituting the values, we find the maximum horizontal distance to be approximately 61.7 meters.
The question probably maybe: What is the maximum horizontal distance the rock travels before hitting the ground, given that a man stands on the roof of a building of height 14.0 m and throws a rock with a velocity of magnitude 26.0 m/s at an angle of 28.0 degrees above the horizontal, ignoring air resistance?
Estimate the number of atoms in your body.
An average adult of weigh 70 kg has approximately [tex]7.0 \times 10^{27}[/tex].
Explanation:
Estimation of Atoms in Human Body
We generally evaluate the amount of elements, liquid, or solid bones in a human body but, we can relate these counts to the atomic level as well. Talking about the approximate amount of Hydrogen, Oxygen and Carbon that we carry in our body, they all make 99% of it neglecting 1% of trace elements.
On the basis of this calculation, we can say that a human body of weight 70 kg has around [tex]7.0 \times 10^{27}[/tex] atoms that are differentiated as 2/3 of hydrogen atoms, 1/4 of Oxygen and only 1/3 of Carbon atoms in the total count.
A turntable reaches an angular speed of "45 rev/min" in "4.10 s" after being turned on. What is its angular acceleration?
Answer:
1.15 rad/s²
Explanation:
given,
angular speed of turntable = 45 rpm
=[tex]45\times \dfrac{2\pi}{60}[/tex]
=[tex]4.71\ rad/s[/tex]
time, t = 4.10 s
initial angular speed = 0 rad/s
angular acceleration.
[tex]\alpha = \dfrac{\omega_f-\omega_0}{t}[/tex]
[tex]\alpha = \dfrac{4.71-0}{4.10}[/tex]
[tex]\alpha = 1.15\ rad/s^2[/tex]
Hence, the angular acceleration of the turntable is 1.15 rad/s²
Calculate the number of vacancies per cubic meter in iron at 850 °C. The energy for vacancy formation is 1.08 eV/atom. Furthermore, the density and atomic weight for Fe are 7.65 g/cm3 and 55.85 g/mol, respectively.
Answer:
The number of vacancies per cubic meter is 1.18 X 10²⁴ m⁻³
Explanation:
[tex]N_v = N*e[^{-\frac{Q_v}{KT}}] = \frac{N_A*\rho _F_e}{A_F_e}e[^-\frac{Q_v}{KT}}][/tex]
where;
N[tex]_A[/tex] is the number of atoms in iron = 6.022 X 10²³ atoms/mol
ρFe is the density of iron = 7.65 g/cm3
AFe is the atomic weight of iron = 55.85 g/mol
Qv is the energy vacancy formation = 1.08 eV/atom
K is Boltzmann constant = 8.62 X 10⁻⁶ k⁻¹
T is the temperature = 850 °C = 1123 k
Substituting these values in the above equation, gives
[tex]N_v = \frac{6.022 X 10^{23}*7.65}{55.85}e[^-\frac{1.08}{8.62 X10^{-5}*1123}}]\\\\N_v = 8.2486X10^{22}*e^{(-11.1567)}\\\\N_v = 8.2486X10^{22}*1.4279 X 10^{-5}\\\\N_v = 1.18 X 10^{18}cm^{-3} = 1.18 X 10^{24}m^{-3}[/tex]
Therefore, the number of vacancies per cubic meter is 1.18 X 10²⁴ m⁻³
The number of vacancies will be "1.18 × 10²⁴ m⁻³".
Vacancy formationAccording to the question,
Number of atoms, [tex]N_A[/tex] = 6.022 × 10²³ atoms/mol
Iron's density, ρFe = 7.65 g/cm³
Iron's atomic weight, AFe = 55.85 g/mol
Energy vacancy formation, Qv = 1.08 eV/atom
Boltzmann constant, K = 8.62 × 10⁻⁶ k⁻¹
Temperature, T = 850°C or, 1123 K
We know the formula,
→ [tex]N_v[/tex] = N × e [[tex]-\frac{Qv}{KT}[/tex]]
= [tex]\frac{N_A\times \rho Fe}{AFe}[/tex] e [[tex]-\frac{Qv}{KT}[/tex]]
By substituting the above values, we get
= [tex]\frac{6.022\times 10^{23}\times 7.65}{55.85}[/tex] e [[tex]- \frac{1.08}{8.62\times 10^{-5}\times 1123}[/tex]]
= 8.2486 × 10²² × [tex]e^{(-11.1567)}[/tex]
= 8.2486 × 10²² × 1.4279 × 10⁻⁵
= 1.18 × 10¹⁸ cm⁻³ or,
= 1.18 × 10²⁴ m⁻³
Thus the answer above is correct.
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A metal wire 1.50 m long has a circular cross section of radius 0.32 mm and an end-to-end resistance of 90.0 Ohms. The metal wire is then stretched uniformly so that its cross-section is still circular but its total length is now 6.75 m. What is the resistance of the wire after stretching? (Units: Ohm.)
Answer:
So after stretching new resistance will be 0.1823 ohm
Explanation:
We have given initially length of the wire [tex]l_1=150m[/tex]
Radius of the wire [tex]r_1=0.32mm=0.32\times 10^{-3}m[/tex]
Resistance of the wire initially [tex]R_1=90ohm[/tex]
We know that resistance is equal to [tex]R=\frac{\rho l}{A}[/tex] ,here [tex]\rho[/tex] is resistivity, l is length and A is area
From the relation we can say that [tex]\frac{R_1}{R_2}=\frac{l_1}{l_2}\times \frac{A_2}{A_1}[/tex]
Now length of wire become 6.75 m
Volume will be constant
So [tex]A_1l_1=A_2l_2[/tex]
So [tex]\pi \times (0.32)^2\times150=\pi \times r_2^2\times 6.75[/tex]
[tex]r_2=1.508mm[/tex]
So [tex]\frac{90}{R_2}=\frac{150}{6.75}\times \frac{1.508^2}{0.32^2}[/tex]
[tex]R_2=0.1823ohm[/tex]
With the new length and cross-sectional area, we determine the new resistance to be approximately 1822.5 Ohms.
To determine the resistance of the wire after it is stretched, follow these steps:
Calculate the initial volume of the wire using the initial length and cross-sectional area.
The initial length (L1) = 1.50 m
The radius (r1) = 0.32 mm = 0.00032 m
Initial cross-sectional area (A1) = πr1² = π (0.00032 m)² = 3.216 × 10⁻⁷ m²
Initial volume (V) = A1 × L1 = 3.216 × 10⁻⁷ m² × 1.50 m = 4.824 × 10⁻⁷ m³
Since volume remains constant, calculate the new radius after stretching.
The new length (L2) = 6.75 m
Initial volume (V) = New volume (V)
V = A2 × L2; thus, A2 = V / L2 = 4.824 × 10⁻⁷ m³ / 6.75 m = 7.148 × 10⁻⁸ m²
New radius (r2) = √(A2 / π) = √(7.148 × 10⁻⁸ m² / π) ≈ 0.000151 m = 0.151 mm
Calculate the new resistance using the resistivity formula.
Resistance (R) = ρ × L / A
Assuming resistivity (ρ) is the same, R1 / R2 = (L1 / A1) / (L2 / A2)
New resistance (R2) = R1 × (L2 / L1)² = 90 Ω × (6.75 m / 1.50 m)²
R2 = 90 Ω × (4.5)² = 90 Ω × 20.25 ≈ 1822.5 Ω
Therefore, the resistance of the wire after stretching is approximately 1822.5 Ohms.
A mass M suspended by a spring with force constant k has aperiod T when set into oscillations on Earth. Its period on Mars,whose mass is about 1/9 and radius 1/2 that of Earth, is mostnearly
A) 1/3 T
B) 2/3T
C)T
D) 3/2T
E) 3 T
Answer:
C)T
Explanation:
The period of a mass-spring system is:
[tex]T=2\pi\sqrt\frac{m}{k}[/tex]
As can be seen, the period of this simple harmonic motion, does not depend at all on the gravitational acceleration (g), neither the mass nor the spring constant depends on this value.
Find the magnitude of the electric field due to a charged ring of radius "a" and total charge "Q", at a point on the ring axis a distance "a" from the ring's center.
Answer:
E=[tex]\frac{KQ}{2\sqrt 2a^2}[/tex]
Explanation:
We are given that
Charge on ring= Q
Radius of ring=a
We have to find the magnitude of electric filed on the axis at distance a from the ring's center.
We know that the electric field at distance x from the center of ring of radius R is given by
[tex]E=\frac{kQx}{(R^2+x^2)^{\frac{3}{2}}}[/tex]
Substitute x=a and R=a
Then, we get
[tex]E=\frac{KQa}{(a^2+a^2)^{\frac{3}{2}}}[/tex]
[tex]E=\frac{KQa}{(2a^2)^{\frac{3}{2}}}[/tex]
[tex]E=\frac{KQa}{2\sqrt 2a^3}[/tex]
[tex]E=\frac{KQ}{2\sqrt 2a^2}[/tex]
Where K=[tex]9\times 10^9 Nm^2/C^2[/tex]
Hence, the magnitude of the electric filed due to charged ring on the axis of ring at distance a from the ring's center=[tex]\frac{KQ}{2\sqrt 2a^2}[/tex]
The magnitude of the electric field due to a charged ring of radius "a" and total charge "Q", at a point on the ring axis a distance "a" from the ring's center is E = Q/[8√2πε₀a²]
Electric field due to a charged ring
The electric field due to a charged ring E is given by
E = Qz/4πε₀[√(z² + R²)]³ where
Q = total charge on ring, z = distance of point from axis of ring and R = radius of ring.Magnitude of electric field due to ring
Given that for this ring R = a and z = a, substituting these values into E, the magnitude of the electric field at a is given by
E = Qz/4πε₀[√(z² + R²)]³
E = Qa/4πε₀[√(a² + a²)]³
E = Qa/4πε₀[√(2a²)]³
E = Qa/4πε₀[2√2a³]
E = Q/[8πε₀√2a²]
E = Q/[8√2πε₀a²]
So, the magnitude of the electric field due to a charged ring of radius "a" and total charge "Q", at a point on the ring axis a distance "a" from the ring's center is E = Q/[8√2πε₀a²]
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"The velocity of a diver just before hitting the water is -10.0 m/s, where the minus sign indicates that her motion is directly downward. What is her displacement during the last 1.16 s of the dive?
Answer:
Explanation:
Given
velocity of diver [tex]u=-10\ m/s[/tex] i.e. downward motion
acceleration due to gravity [tex]a=g=-9.8\ m/s^2[/tex]
time [tex]t=1.16\ s[/tex]
using equation of motion
[tex]y=ut+\frac{1}{2}at^2[/tex]
[tex]y=(-10)\cdot 1.16-\frac{1}{2}(-9.8)(1.16)^2[/tex]
[tex]y=-11.6-6.593[/tex]
[tex]y=-18.19\ m[/tex]
I.e. in downward direction
The displacement of the diver during the last 1.16 seconds of her dive is -11.6 meters. The negative sign indicates a downward movement.
Explanation:In physics, displacement is the overall change in position of an object. It is calculated by multiplying velocity and time. In this case, the velocity of the diver is -10.0 m/s (a negative sign indicating downward motion) and the time is 1.16 s. To find the displacement, multiply the velocity and the time: (-10.0 m/s) × (1.16 s) = -11.6 m. The minus sign still indicates downward direction, and it means that the diver moved 11.6 meters downward in the last 1.16 seconds of her dive.
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