A car slams on its brakes, though not able to stop in time before striking a car in front of him. The car is 2420 kg. The one that was rear ended was 1650 kg. The bumpers of vehicles lock altogether. And encompass a coefficient of kinetic friction of .76. The vehicles slide a distance of 4.11 meters after impact. Determine how fast were the vehicles moving instantly after the impact? Determine how fast was the car moving that rear-ended the other car?