Aball with a momentum of +4.0 kg m/s hits a wall and bounces straight back without losing any kinetic energy. the change in momentum of the ball is?

8 kgm/s

Explanation:

Since the formula for kinetic energy is:

where m is the mass and v is the velocity. If energy is conserved, mass is conserved, it would mean the speed is the same as well. And since the momentum is defined as the product of mass and velocity. The only change in velocity, and also momentum is the direction.

So the ball momentum would change from 4kgm/s to -4kgm/s. A change of 8 kgm/s