Question

The angular speed of digital video discs (DVDs) varies with whether the inner or outer part of the disc is being read. (CDs function in the same way.) Over a 133min playing time, the angular speed varies from 570rpm to 1600rpm .Assuming it to be constant, what is the angular acceleration (in/rads sec ) of such a DVD?

Answer 1

Answer:

α = 0.0135 rad/s²

Explanation:

given,

t = 133 min = 133 x 60 = 7980 s

angular speed varies from 570 rpm to 1600 rpm

now,

570 rpm = $570 \times \dfrac{2\pi}{60}$

              = 59.69 rad/s

1600 rpm =  = $570 \times \dfrac{2\pi}{60}$

              = 167.6 rad/s

using equation of rotational motion

ωf = ωi + αt    

167.6 = 59.7 + α x 7980

α  x 7980 = 107.9

α = 0.0135 rad/s²