Question

A 7300-kg satellite has an elliptical orbit, as in the figure. The point on the orbit that is farthest from the earth is called the apogee and is at the far right side of the drawing. The point on the orbit that is closest to the earth is called the perigee and is at the far left side of the drawing. Suppose that the speed of the satellite is 2730 m/s at the apogee and 8450 m/s at the perigee.

(a) Find the work done by the gravitational force when the satellite moves from the apogee to the perigee.

(b) Find the work done by the gravitational force when the satellite moves from the perigee to the apogee

Answer 1

Work done? lets do it with potential theory.

PE=force*r=ms*g*re^2/r

where r is the distances from center of Earth, me is mass satellite.

Now enegy change from one point to the other:

from apogee to perigee
Work=ms*g*re^2 (1/2730-1/8450)

check my thinking and math.