Question

please give this two answers

Answer 1

a) in a closed system the total momentum before an event is equal to the total momentum after the event.

b)momentum before crashing of body A=20kg m/s

momentum before crashing of body B= 0kg m/s ( the body is at rest)

momentum after crashing of body A= 2kg * v

momentum after crashing of body B=5kg*v

2v+5v=20+0

7v=20    

v=20/7 i.e ......2.85 m/s