physics
posted by Brittany .
A 3 kg toy car with a speed of 10 m/s collides headon with a 2 kg car traveling in the opposite direction with a speed of 3 m/s. If the cars are locked together after the collision with a speed of 4.80 m/s, how much kinetic energy is lost?

find the velocity after collision:
3*10+2*(3)=((3+2)V
V=(306)/5=5m/s
KE= 1/2 m v^2=1/2 (5)(25)=75/2 Joules
What was the starting energy?
1/2 (3*100)+1/2*2*9=159Joules
check my math.