Question

A 2510 kg car, moving at 23.0 m/s, runs into a car that has a mass of 1750 kg

and is moving at 12.3 m/s in the same direction. The cars stick together after
the collision. Assuming momentum is conserved, what is their final velocity?
A. 18.6 m/s
B. 16.4 m/s
C. 19.3 m/s
D. 21.1 m/s

Answer 1

By conservation of momentum,

(2510 kg) (23.0 m/s) + (1750 kg) (12.3 m/s) = (4260 kg) v

where v is the velocity of the combined cars.

Solve for v :

(4260 kg) v = 79 255 kg•m/s

v ≈ 18.6 m/s