A 0.l-kg mass travels along a horizontal air track at a speed of I m/s. It makes an elastic collision with another, identical mass that is initially at rest on the track. Following the impact the total momentum and kinetic energy are the same as before the impact. the total momentum is the same as before the impact, but the total kinetic energy is less. the kinetic energy is conserved, but the momentum after the impact is less than before. the momentum is shared equally between the two masses alter the impact.