Question

A disc rotates with a uniform angular acceleration of 2.0 rad/s${}^2$ about its axis. If the disc starts from rest, how many revolutions will it make in the first 10 seconds?

• A. 16
• B. 32
• C. 8
• D. None of the above

Answer 1

The correct option is A 16

The angular displacement in the first 10 seconds is given by
$\theta ={\omega }_{0}t+\frac{1}{2}\alpha t^2=\frac{1}{2}\left(2.0rad/s^2\right)(10s{)}^2=100rad$
As the wheel turns by 2$\pi$ radian in each revolution, the number of revolutions in 10 s is
$n=\frac{100}{2\pi }=16$.