A rigid rod pivots about one end

PHYSICS · Single correct · A Level · Physics · Engineering physics · Engineering physics

Problem

A rigid rod pivots about one end. A net external torque that varies with time as

\tau(t) = (0.60\,\text{N}\cdot\text{m})\,t

(with

t

in seconds) acts on the rod for

3.0\,\text{s}

. The rod has moment of inertia

0.30\,\text{kg}\cdot\text{m}^2

about the pivot and starts from rest. What is the rod’s angular speed at

t = 3.0\,\text{s}

? (a)

4.5\,\text{rad}\,/\text{s}

(b)

18\,\text{rad}\,/\text{s}

(c)

9\,\text{rad}\,/\text{s}

(d)

6.0\,\text{rad}\,/\text{s}