Walker, Halliday & Resnick — Gravitation: Problem 25

25 Figure 13-27 gives the potential energy function \(U(r)\) of a projectile, plotted outward from the surface of a planet of radius \(R_s\). If the projectile is launched radially outward from the surface with a mechanical energy of \(-2.0 \times 10^9 \text{ J}\), what are (a) its kinetic energy at radius \(r = 1.15R_s\) and (b) its turning point (see Module 8-3) in terms of \(R_s\)?