Problem: A computer disk drive is turned on starting from rest and has a constant angular acceleration. If it took 0.750 seconds for the drive to make its second revolution,1. How long did it take to make the first complete revolution?2. What is its angular acceleration in rad/s2?

FREE Expert Solution

(a)

For the two revolutions, time, t' = t + 0.750 s

The angular displacement for one revolution, Δθ = 2π rad

For two complete revolutions, 2Δθ= 4π rad

The rotational kinematic relation:

θ=ω0t+12αt2

For the first complete revolution:

2π=0+12αt2

4π = αt2 

For two complete revolutions:

4π=0+12α(t+0.750)28π=α(t2+1.5t+0.5625)

8π = α(t2 + 1.5t + 0.5625)

Dividing the expression for two complete revolutions and that of one complete revolution:

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Problem Details

A computer disk drive is turned on starting from rest and has a constant angular acceleration. If it took 0.750 seconds for the drive to make its second revolution,


1. How long did it take to make the first complete revolution?


2. What is its angular acceleration in rad/s2?

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