Answer to Question #267339 in Physics for francene

Question

If a 900.0 kg sports car slows to 15.0 m/s to check out an accident scene and the 1500.0 kg pick up behind him continues traveling at 35.0 m/s, with what velocity will the two move if they lock bumpers after a rear-end collision?

Answer 1

The common velocity will be

$$v_c=\frac{mv+Mu}{m+M}=27.5\text{ m/s}.$$