A green 4 kg toy car with a speed of 5 m/s collides head-on with a stationary yellow 1-kg car. After the collision, the cars are locked together with a speed of 4 m/s. How much kinetic energy is lost in the collision?

a. What is the kinetic energy of the green 4-kg toy car BEFORE the collision?

b. What is the kinetic energy of the yellow 1-kg toy car BEFORE the collision?

c. What is the kinetic energy of the two cars AFTER the collision?