Estimate the following problem given below:
Problem: A proton (mass 1.67 x 10-27) is moving at 1.25 x 10-6 m/s directly towards a stationary helium nucleus (mass 6.64 x 10-27).
Part I: After a head-on elastic collision, what is the protons velocity?
Part II: After a head-on collision, what is the helium's velocity?
Please write the step and solution.