forces - conservation of momentum

Question 1

A van with a mass of 2000kg is travelling at 30 m/s
It collided with a stationary car of 800kg
Bath van and car continue moving together
Calculate velocity of van and car together

Answer 1

1. Calculate total momentum of van and car before the collision
   Van:
   momentum= mass x velocity
   2000 x 30 =60,000 kg m/s
   car: momentum = 0
   total momentum: 0 + 60 000 = 60 000 kg m/s

momentum always conserved so total momentum after collision is also 60 000 kg m/s

velocity = momentum / mass
60 000 / (2000+800) = 21.4 m/s