Answer: 
Explanation:
Given
CD has a playing time of 
Initial angular speed of CD is 
Final angular speed of DC is 
Angular speed, when rpm is given


Final speed

Using equation of angular motion

Insert the values

Magnitude of angular acceleration is 
Newtons Third law of motion
Answer:
Explanation:
initial angular velocity, ωo = 0
angular acceleration = α
time = t
let the angular velocity after time t is ω.
Use first equation of motion for rotational motion
ω = o + α t
ω = αt
The angular momentum is given by
Angular momentum = moment of inertia x angular velocity
L = I x ω
L = I x αt
L = I α t
There the potential difference is -0. 553 keQ/R.
What is Electric potential ?
The amount of labor required to convey a unit of electric charge from a reference point to a given place in an electric field is known as the electric potential (also known as the electric field potential, potential drop, or the electrostatic potential).
Electric potential at point 0,
V1 = ke Q/R
Electric potential at x= 2R
V2= keQ/ root5. R
Therefore potential difference is
dV = V2 - V1
Putting the values we get ,
dV = -0. 553 keQ/R
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