Question

A simple pendulum consisting of a ball of mass $m$ tied to a string of length $l$ is made to swing on a circular arc of angle $\theta$ in a vertical plane. At the end of this arc, another ball of mass m is placed at rest. The momentum transferred to the ball at rest by the swinging ball is:

• A. $m\theta /\sqrt{l/g}$
• B. $m\theta /\sqrt{g/l}$
• C. $2\pi m/\sqrt{l/g}$
• D. zero

Answer 1

The correct option is D zero

When particle comes at rest,then its velocity will be zero. We know the formula for momentum is $P$=$mv.$
but mass is constant,$P=m\frac{d\left(v\right)}{dt}$
$P$ will be zero