Question

A 4.0 kg object is moving at 5.0 m/s NORTH. It strikes a 6.0 kg object at rest. The objects have an elastic collision and move in the NORTH or SOUTH direction. The velocity of the 4.0 kg object after the collision is


a) 1.0 m/s NORTH
b) 4.0 m/s NORTH.
c) 1.0 m/s SOUTH.
d) 4.0 m/s SOUTH.

Answer 1

sorry................m..mm.m....

Answer 2

Answer: 1 m/s of South

Explanation:

Here the collision is perfectly elastic

So Momentum is conserved

m1 v1 = m2 v2

4*5 = 6* v2

v2 = 20/6 = 3.33 m/s

So the velocity of 6kg = 4 m/s north

Therefore, relative velocity = 5m/s

v2 - v1 = 5

4 - v1 = 5 - v1 = 1

Negative sign indicates that the direction of velocity are opposite site.

Hence, the velocity of 4kg mass after the collision is 1 m/s of south