Two small solid metal spheres A and B have equal radii and are in a vacuum. Their centres are 
apart. Sphere A has charge 
and sphere B has charge 
. The arrangement is illustrated in the figure below.
Point P lies on the line joining the centres of the spheres and is a distance of 
from the centre of sphere A.
Calculate the electric potential at point P.
A silver-107 nucleus (
) has speed 
when it is a long distance from point P. Use your answer in (a) to calculate the minimum value of speed such that the nucleus can reach point P.
.
.
