Answer:
Explanation:
Given:
- original frequency of sound wave,
- speed of the sound source,
- original speed of sound wave from the source,
<u>According to the Doppler's effect:</u>
The sound is reflected from the wall and the source is moving towards the wall and observer is also riding the same source.
The velocity of the observer, 
In the graph of the force vs the time:
Force is the gradient of the momentum versus the time.
If we get the area under the curve in this graph:
it will be calculated as : force * time
which gives the change in momentum or the impulse.
Therefore, the area under the curve <span>represents the impulse of the force in a graph of force versus time</span>
Answer:
a) before immersion
C = εA/d = (8.85e-12)(25e-4)/(1.31e-2) = 1.68e-12 F
q = CV = (1.68e-12)(255) = 4.28e-10 C
b) after immersion
q = 4.28e-10 C
Because the capacitor was disconnected before it was immersed, the charge remains the same.
c)*at 20° C
C = κεA/d = (80.4*)(8.85e-12)(25e-4)/(1.31e-2) = 5.62e-10 F
V = q/C = 4.28e-10 C/5.62e-10 C = 0.76 V
e)
U(i) = (1/2)CV^2 = (1/2)(1.68e-12)(255)^2 = 5.46e-8 J
U(f) = (1/2)(5.62e-10)(0.76)^2 = 1.62e-10 J
ΔU = 1.62e-10 J - 5.46e-8 J = -3.84e-8 J
