A uniform meter stick of mass is pivoted about one end so it can rotate freely in a…

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

Problem

A uniform meter stick of mass

0.60\,\text{kg}

is pivoted about one end so it can rotate freely in a vertical plane. A small

0.40\,\text{kg}

mass is firmly attached to the free end of the stick. Immediately after a perpendicular force is applied at the midpoint of the stick (exactly

0.50\,\text{m}

from the pivot), the system rotates with an angular acceleration of

4.0\,\text{rad}\,\text{s}^{-2}

. Neglect gravity during the instant the force is applied. What is the magnitude of the applied force? (a)

2.4\,\text{N}

(b)

6.4\,\text{N}

(c)

4.8\,\text{N}

(d)

3.6\,\text{N}