Question

What velocity must a car with a mass of 1120 kg have in order to have the same momentum as a 2310 kg pickup truck traveling at 21 m/s to the east?

Answer 1

The momentum of a 2310 kg pickup truck traveling at 21 m/s is

$$p_1=Mv=2310\cdot21=48510\text{ kg m/s}.$$

It must be the same as the momentum of a 1120 kg car:

$$mu=p_2,\\ p_1=p_2,\\ Mv=mu,\\\space\\ u=\frac{Mv}{m}=\frac{48510}{1120}=43.3\text{ m/s}.$$