Question

If applied torque on a system is zero, i.e., $\tau =0$ , then for that system:

• A. $\omega =0$
• B. $\alpha =0$
• C. $J=0$
• D. $F=0$

Answer 1

Answer: (B)

$\tau =I\alpha$ (where$\tau =$ torque )
$I=$ moment of inertia
$\alpha =$ angular acceleration
if $\tau =0$
$I\alpha =0$
But $I\ne 0$
$\therefore \alpha =0$