A child pulls a toy wagon with a force of 25.0 N for a distance of 8.5M. How much work did the child do on the wagon?

A capacitor is formed from two concentric spherical conducting shells separated by vacuum. The inner sphere has radius 11.0 cm ,

viktelen [127]

Part A)
First of all, let's convert the radii of the inner and the outer sphere:
$r_A = 11.0 cm = 0.110 m$
$r_B = 16.5 cm=0.165 m$
The capacitance of a spherical capacitor which consist of two shells with radius rA and rB is
$C=4 \pi \epsilon _0 \frac{r_A r_B}{r_B- r_A}=4\pi(8.85 \cdot 10^{-12}C^2m^{-2}N^{-1}) \frac{(0.110m)(0.165m)}{0.165m-0.110m}=$
$=3.67\cdot 10^{-11}F$

Then, from the usual relationship between capacitance and voltage, we can find the charge Q on each sphere of the capacitor:
$Q=CV=(3.67\cdot 10^{-11}F)(100 V)=3.67\cdot 10^{-9}C$

Now, we can find the electric field at any point r located between the two spheres, by using Gauss theorem:
$E\cdot (4 \pi r^2) = \frac{Q}{\epsilon _0}$
from which
$E(r) = \frac{Q}{4 \pi \epsilon_0 r^2}$
In part A of the problem, we want to find the electric field at r=11.1 cm=0.111 m. Substituting this number into the previous formula, we get
$E(0.111m)=2680 N/C$

And so, the energy density at r=0.111 m is
$U= \frac{1}{2} \epsilon _0 E^2 = \frac{1}{2} (8.85\cdot 10^{-12}C^2m^{-2}N^{-1})(2680 N/C)^2=3.17 \cdot 10^{-5}J/m^3$

Part B) The solution of this part is the same as part A), since we already know the charge of the capacitor: $Q=3.67 \cdot 10^{-9}C$ . We just need to calculate the electric field E at a different value of r: r=16.4 cm=0.164 m, so
$E(0.164 m)= \frac{Q}{4 \pi \epsilon_0 r^2}=1228 N/C$

And therefore, the energy density at this distance from the center is
$U= \frac{1}{2}\epsilon_0 E^2 = \frac{1}{2} (8.85\cdot 10^{-12}C^2m^{-2}N^{-1})(1228 N/C)^2=6.68 \cdot 10^{-6}J/m^3$

8 0

3 years ago

The speed of a wave changes depending on the temperature of the medium. What do you think is the reason for this?

igor_vitrenko [27]

Answer: Because of the different wave speed from light and sound. Explanation: There is a major difference between the speed wave of light and sound, light travels at 186, 282 miles per second, and sound can travel at different speeds and its significantly slower so it is easier to measure it

Explanation:

5 0

3 years ago

Sort the sentences based on whether they describe radio waves, visible light waves, or both.

valentina_108 [34]

The electromagnetic spectrum includes a continuous spectrum of wavelengths that include:

Radio waves, microwaves, infrared light, visible, ultraviolet, X-rays, gamma rays

The wavelength decreases from radio waves to gamma rays, whereas the energy increases along the same direction.

In the given example, radio waves have a lower energy and higher wavelength than visible light. The latter can be perceived by the human eye, whereas radio waves are not visible to the human eye.

1) They have colors = visible light

2) They can travel in a vacuum = both

3) They have energy = both

4) They’re used to learn about dust and gas clouds = radio waves

5) They’re used to find the temperature of stars = visible light

6)They’re invisible = radio waves

6 0

3 years ago

If the phase of the vibrating sources was changed so that they were vibrating completely out of phase, what effect would this ha

Over [174]

Answer:

There would be complete destructive interference.

Explanation:

This is because since the waves are completely out of phase, the phase difference is half wavelength, that is the phase angle is 180°. The vibrating sources are 180° out of phase with each other.

Since this is the case, the crest of the one source meets the trough of the other, this causes the resultant vibrational wave to cancel out, thus producing a destructive interference pattern.

Since the vibrating sources are completely out of phase, every point they meet is completely out of phase, so the resultant interference pattern would produce a complete destructive interference pattern of no wave.

4 0

3 years ago

A lizard ran 3 meters from his rock to his friend's house. He ran

lbvjy [14]

Answer:

4.5 meters

Explanation:

3 meters to his friend's house. +3

Halfway back. +1.5

3+1.5

=4.5

4.5 meters in total

5 0

3 years ago

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