4. The earth is in an elliptical orbit around the sun; that means its distance from the sun varies with time. An exaggerated version of this is shown below with the earth drawn at both the perihelion (the closest the earth ever is to the sun, 1.47 x 105km) and the aphelion (the furthest the earth ever is from the sun, 1.52 x 10*km.) On average, the earth travels at 29.8km/s relative to the sun in its orbit, and its mass is 5.97 x 10" kg. (a) What is the magnitude of earth's angular momentum? (b) What is the earth's speed at the aphelion? (c) What is the earth's speed at the perihelion