## Problem Statement

**58)
A heavy car A of mass 2000 kg travelling at 10 m/s has a head-on collision with
a sports car B of mass 500 kg. If both cars stop dead on colliding, what was
the velocity of car B ?**

## Solution

Say, velocity of B before collision be V m/s

Initial momentum = 2000 x 10 + 500 x V kg m/s

Final momentum = 0

As per law of conservation of linear momentum:

20000 + 500 V =0

=> V = – 20000/500 = – 40 m/s

So velocity of car B was 40 m/s towards A.(they had head on collision)

Question Set – Physics Problems for grade 9

Solution to problems – class 9 – Set 1 Q 58