A body of mass \(M\), carrying charge \(Q\), falls from rest from a height \(h\)
(above the ground) near the surface of the Earth, where the gravitational
acceleration is \(g\) and there is an electric field with a constant component
\(E\) in the vertical direction.
a) Find an expression for the speed, \(v\), of the body when it reaches the
ground, in terms of \(M, Q, h, g,\) and \(E\).
b) The expression from part (a) is not meaningful for certain values of \(M\),
\(g, Q\) and \(E\). Explain what happens in such cases.