A tiny sphere of mass 7.30 µg and charge 2.80 nC is initially at a distance of 1.74 µm from a fixed charge of +9.09 nC.
(a) If the 7.30-µg sphere is released from rest, find its kinetic energy when it is 0.500 µm from the fixed charge.
(b) If the 7.30-µg sphere is released from rest, find its speed when it is 0.500 µm from the fixed charge.