A neutron, a proton, and an electron are initially at the same distance from a relatively large stationary nucleus moving at a constant velocity. Assume the masses of the proton and neutron are equal.

Question

1. Which is the first particle to reach the nucleus?
2. Which particle experiences the greatest force?
Which particle experiences the greatest acceleration?

I need help and explanation with these questions! THANKS A LOT!

Answer 1

The electron will be attracted, and accelerate, the proton will be repelled, and it will deaccelerate.

Answer 2

but which particle experiences the greatest force?

Answer 3

1) The neutron will reach the nucleus first. While they are moving toward the nucleus, the neutron is moving at constant belocity, the proton is experiencing a repulsive force and thus decellerating, the electron is experiencing an attractive force and thus it is accelerating.

So, the electron will initially overtake the proton and the neuron. However, when the electon comes close to the nucleus it will lose energy due to Bremsstrahlung, see here:

http://en.wikipedia.org/wiki/Bremsstrahlung

The electron will ultimatly end up in an bound state (an orbit around the nucleus), so it won't reach the nucleus at all!

Due to the electrostatic repulsion, the proton can only reach the nucleus if its intial velocity is high enough.

The neutron will lose its momentum only when it hits the nucleus, while the proton will lose part of its momentum gradually. So, the neutron will experience the greatest force and acceleration upon impact.