Question

A grind-stone starts revoiving from rest, it its angular acceleration is 4.0 $rad/se{c}^2$ (uniform) then after 4 sec. What is its angular displacement & angular velocity respectively -

• A. 32 rad, 16 rad/sec
• B. 16 rad, 32 rad/sec
• C. 64 rad, 32 rad/sec
• D. 32 rad, 64 rad/sec

Answer 1

The correct option is A 32 rad, 16 rad/sec

Angular displacement $\left(\theta \right)=\frac{1}{2}\alpha t^2$

Where $\theta$ = angular acceleration

Angular displacement $=\frac{1}{2}\times 4\times 4^2=32rad$

Here, angular velocity (w) = $\alpha t$

$w=4\times 4$

$=16\frac{rad}{sec}$

Hence option (A) is correct