In the scenario described in Exercise 3.8, what type of collision must occur between the nuclear particles in a real reactor, and what particles do you think participated in this collision if the...

In the scenario described in Exercise 3.8, what type of collision must occur between the nuclear particles in a real reactor, and what particles do you think participated in this collision if the atomic nucleus was a hydrogen atom?

Exercise 3.8

An atomic nucleus initially at rest in a reactor core collides with another nuclear particle whose initial velocity is 10,000 m/s. After just one collision, the nuclear particle comes to a complete stop, and the atomic nucleus heads off in the same direction with the same average velocity. What can we conclude about the mass of the atomic nucleus in this case? If the incoming particle is an alpha particle, what element did the alpha particle collide with?