posted by mk .
A 3 kg toy car with a speed of 10 m/s collides head-on with a 2 kg car traveling in the opposite direction with a speed of 2 m/s. If the cars are locked together after the collision with a speed of 5.20 m/s, how much kinetic energy is lost?
figure final velocity from conservation of momentum. Then, use that velocity to calcualte the final KE. Compare it with the initial KE