28. An elliptical orbit can be analyzed using conservation of angular momentum and mechanical energy. The distance between Earth, mass 5.972 × 1024 kg, and Sun, mass 1.989 × 1030 kg, varies from 147 to 152 Gm. (a) Use the formula UG = – Gm1m2/r to find the change in potential energy that occurs moving from the farthest distance to the nearest. (b) Given that the speed of Earth at its farthest point is 29.29 km/s, use conservation of energy to find its speed at the nearest point. (c) Calculate the angular momentum of Earth at each extreme and show that it is equal.

28. An elliptical orbit can be analyzed using conservation of angular momentum and mechanical energy. The distance between Earth, mass 5.972 × 1024 kg, and Sun, mass 1.989 × 1030 kg, varies from 147 to 152 Gm. (a) Use the formula UG = – Gm1m2/r to find the change in potential energy that occurs moving from the farthest distance to the nearest. (b) Given that the speed of Earth at its farthest point is 29.29 km/s, use conservation of energy to find its speed at the nearest point. (c) Calculate the angular momentum of Earth at each extreme and show that it is equal.