Problem
A proton (q = +e, m = 1.6725 x 10 -24 grams) moves head-on at a fixed silver (Z= 47) nucleus. If the distance of closest approach (where the proton will temporarily stop and turns around) is 0. 911 nm, what is the kinetic energy (in eV and in Joules) and the speed (in m/s) of the proton when it was 49.5 nm from the silver nucleus?