Question

Two billiard balls A and B, each of mass 50 g and moving in opposite directions with speed of 5 $m{s}^{-1}$ each, collide and rebound with the same speed. The impulse imparted to each ball is:

• A. $0.25Kgm{s}^{-1}$
• B. $0.5Kgm{s}^{-1}$
• C. $0.1Kgm{s}^{-1}$
• D. $0.125Kgm{s}^{-1}$

Answer 1

Answer: (B)

$0.5Kgm{s}^{-1}$

Mass of each ball$,m=50g=0.05kg$

Initial velocity, $v_1=5m/s$

Initial Momentum , $P_1=m{v}_1=0.05\times 5=0.25kgm/s$

After collision, the direction of velocity of each ball is reversed on rebounding.

Final momentum, $P_2=m\times (-v_1)=0.05\times (-5)=-0.25kgm/s$

Impulse imparted on each ball = Change in momentum of each ball after collision

$J=P_1-P_2=0.25-(-0.25)=0.5kgm/s$

$\therefore$ Impulse imparted due to one ball after collision on another is equal to $0.5kgm/s$