Explanation:
When Michelson-Morley apparatus is turned through
then position of two mirrors will be changed. The resultant path difference will be as follows.

Formula for change in fringe shift is as follows.
n = 

v = 
According to the given data change in fringe is n = 1. The data is Michelson and Morley experiment is as follows.
l = 11 m
c =
m/s
Hence, putting the given values into the above formula as follows.
v = 
= 
= 
Thus, we can conclude that velocity deduced is
.
Force, newtons 3rd law of motion stated for every action there is an equal and opposite reaction
To solve this exercise it is necessary to apply the kinematic equations of angular motion.
By definition we know that the displacement when there is constant angular velocity is

From our given data we know that,



Moreover we know that

Therefore for time t=8.1s we have,



That number in revolution is:


Here, we see that there are 15 complete revolutions
And 0.108 revolutions i not complete, so the tunable rotation is

Therefore the angle of the speck at a time 8.1s is 
Answer:
5.1*10^3 J/m^3
Explanation:
Using E = q/A*eo
And
q =75*10^-6 C
A = 0.25
eo = 8.85*10^-12
Energy density = 1/2*eo*(E^2) = 1/2*eo*(q/A*eo)^2 = [q^2] / [2*(A^2)*eo]
= [(75*10^-6)^2] / [2*(0.25)^2*8.85*10^-12]
= 5.1*10^3 J/m^3