At a busy intersection, a 1320-kg car traveling west with a speed of 12 m/s collides head-on with a minivan traveling east with a speed of 9.4 m/s. The cars stick together and move with a velocity of 1.5 m/s to the east after the collision. What is the mass of the minivan

p = mv so this question pertains to conservation of momentum.

The momentum of the car is 1320*12 = 15840kgms^-1

For the sake of easiness and the fact negatives are annoying, I will assume east to be positive.

So we know 9.4m - 15840 = (1320+m) * 1.5

9.4m - 15840 = 1980+1.5m

Rearranging to solve for m

7.9m = 17820

m = 2255.70 = 2300kg to 2sf