A truck, a car and a motorcycle have equal kinetic energies. If equal, stopping forces are applied and they stop after travelling a distance of X, Y and Z respectively, then

The work done by the stopping force in bringing a body to rest is equal to its initial kinetic energy.

Work done = Force × Distance = Kinetic Energy

If the same retarding force is applied to the truck, car, and motorcycle, and all three have the same kinetic energy, then:

Distance travelled before stopping = KE / Force

Since KE is equal for all and Force is also equal, the stopping distance will be the same for each vehicle.

Therefore:

X = Y = Z

Hence, the correct option is E.