If an object of mass m1 = 0.55 is sliding without friction in the +x-direction on a level surface at a speed of = 0.72 m/ and it collides with a stationary object of mass m1 = 0.55 determine the total initial and total final momenta (before and after the collision) as well as the total initial and final mechanical energy (before and after the collision) for a perfectly elastic collision.