Calculating Initial Kinetic Energy for Alpha Particle Approaching Nickel Nucleus

[NikkiNik]

Homework Statement

What initial kinetic energy must an alpha particle have if it is to approach a stationary nickel nucleus to within a distance of 24.6 fm?

Homework Equations

not sure

The Attempt at a Solution

I'm not really sure how to connect the KE with the distance of the nucleus. Can someone please give me a hint

 

[ideasrule]

Here's a hint: conservation of energy.

 

[tiny-tim]

I'm not really sure how to connect the KE with the distance of the nucleus. Can someone please give me a hint

Hint: what is the PE at that distance?