7. a 1000 kg car is rolling down the street at 2.5 m/s. how fast would a 2500 kg car have to
collide into it in order to bring it to rest (0 m/s)?

A980-kg sports car collides into the rear end of a 2300-kg suv stopped at a red light. the bumpers lock, the brakes are locked, and the two cars skid forward 2.6m before stopping.the police officer, estimating the coefficient of kinetic friction between tires and road to be 0.80, calculates the speed of the sports car at impact. what was that speed?