Acar with a mass of 800 kg, moving at +15 m/s, crashes head on with a 1500 kg truck moving at -45.5 m/s in the opposite direction. if the two cars become intertwined, with what velocity does the wreckage move?

v = -24.5 m/s

Explanation:

Use conservation of momentum P = m*v. Unless there are external forces involved, total momentum must be conserved.

P: momentum

m: mass

v: velocity

1. calculate the total momentum before the collision:

2. the total momentum after the collision must not change:

3. after the collision the velocity of the car is the same as the velocity of the truck:

4. combining 2. and 3.:

5. this equation only has one unknown and can be solved for v: