A point mass \(m\) is located at the origin. Let \(Q\) be the flux of the gravitational field \(\mathbf{F}=-G m \frac{\mathbf{e}_{r}}{r^{2}}\) through the cylinder \(x^{2}+y^{2}=R^{2}\) for \(a \leq z \leq b\), including the top and bottom (Figure 18). Show that \(Q=-4 \pi G m\) if \(a

b a m R