Question

A ball with origanl momentum +4.0 kgm/s hits a wall and bouncea straight back without losing any kinetic energy. The change in momentum of ball is
A) +4 Ns
B) - 4 Ns
C) +8 Ns^ 2
D) -8 Ns​

Answer 1

$\huge \underline \green{\sf{ Answer :- }}$

• change in the ball's momentum is : ΔP=−8 kg⋅ms

$\small \underline {\sf{ Explanation :-}}$

Pb represents momentum of ball (before hitting)

Pb=4.0 kg⋅ms

Pa represents momentum of ball (after hitting)

Pa=−4.0 kg⋅ms

ΔP:change of momentum

ΔP=Pa−Pb

ΔP=−4.0−4.0

ΔP=−8 kg.ms