College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 59

A proton and an alpha particle (charge = 2 e , mass = 6.64 × 10 27 kg) are initially at rest, separated by 4.00 × 10 15 m. (a) If they are both released simultaneously, explain why you can't find their velocities at infinity using only conservation of energy. (b) What other conservation law can be applied in this case (c) Find the speeds of the proton and alpha particle, respectively, at infinity.