(newtons first law)
conservation of momentum law states :
momentum before collision = momentum after collision
momentum p (kg-m/s)= mass * velocity
say moving car=1 000 kg, velocity = 10 m/s then p = 1 000*10= 10 000 kg-m/s
say still car = 2 000 kg, velocity = 0 m/s then p = 2 000* 0 = 0 kg-m/s
total momentum prior to collision = 10 000 + 0 = 10 000 kg-m/s
momentum after collision = 10 000 kg-m/s
mass now = 1 000 kg+2 000 kg = 3 000 kg
10 000 = 3 000 kg* velocity m/s
10 000/3 000 = velocity
3.33 m/s = velocity after collision
an impulse is a force applied over time , momentum is exclusive of external forces and a perfect collision is implied
