A3 kg toy car with a speed of 9 m/s collides head-on 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 4.20 m/s, how much kinetic energy is lost?

Loss in kinetic energy is 86.4 J.

Explanation:

It is given that,

Mass of first car, m₁ = 3 kg

Velocity of first car, v₁ = 9 m/s

Mass of second car, m₂ = 2 kg

Velocity of second car, v₂ = -3 m/s (opposite direction)

If the cars are locked together after the collision with a speed of 4.20 m/s, V = 4.2 m/s

It is a case of inelastic collision. Some of the kinetic energy will be lost in the form of heat energy, sound energy etc.

Initial kinetic energy,

Final kinetic energy,

Kinetic energy lost,

So, 86.4 J of kinetic energy is lost. Hence, this is the required solution.