Q77 / 160 · JIPMER 2014 · Physics

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

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

Solution

$\begin{aligned} \tau= & l \alpha \\ & I=\text { moment of inertia } \\ & \alpha=\text { angular acceleration }\end{aligned}$ $\begin{array}{ll}\text { If } & \tau=0 \Rightarrow l \alpha=0 \\ \text { But } & I \neq 0\end{array}$ $\therefore \quad \alpha=0$

Hence, the correct answer is option: 'B'.

More Rotational Motion Questions