A990-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 2.5 m before stopping. the police officer, knowing that the coefficient of kinetic friction between tires and road is 0.80, calculates the speed of the sports car at impact. what was that speed? (you will need to split the problem into two parts. in one part you will use conservation of linear momentum. in the other part you will use the work-energy principle.)