Question

A constant net torque is applied to an object. Which one of the following will NOT be constant?

Answer 1

Answer:

B) Angular velocity

Explanation:

The equivalent of Newton's second law for rotational motions is

$\tau = I \alpha$

where

$\tau$ is the net torque on a system

I is the moment of inertia

$\alpha$ is the angular acceleration

From the formula, we observe that if a constant net torque (=different from zero) is applied to an object, than the angular acceleration of the object $(\alpha)$ is non-zero and constant.

But angular acceleration is defined as the rate of change of the angular velocity, $\omega$:

$\alpha = \frac{d\omega}{dt}$

so, a non-zero angular acceleration means that the angular velocity is changing, so the correct answer is B.