Question

A batsman hits back a ball straight in the direction of the bowler without changing its initial speed of $12m{s}^{-1}$. If the mass of the ball is $0.15kg$, determine the change in momentum of the ball. (Assume linear motion of the ball)

• A. $3.6kgm/s$
• B. $5kgm/s$
• C. $3.5kgm/s$
• D. $7kgm/s$

Answer 1

The correct option is A $3.6kgm/s$

The initial momentum of ball $P_1=m\overrightarrow{v}$, after batsman hits ball and reverses its direction, momentum of ball $P_2=-m\overrightarrow{v}$
Magnitude of change in momentum $\Delta p=|P_2-P_1|=|-2m\overrightarrow{v}|=2m\left|\overrightarrow{v}\right|$
from data given in question $m=0.15kg;\left|\overrightarrow{v}\right|=12m/s$
$\Delta P=2\times 0.15\times 12=3.6kgm/s$