A 1,500kg truck moving at 15 m/s strikes a 750 kg automobile stopped at a traffic light the vehicle. The vehicles hook bumpers and skid together at 10 m/s. What is the decrease in kinetic energy?

Answer 1

original KE=1/2 1500*25^2
new KE=1/2 (1500+750)10^2

Answer 2

10