Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
A satellite orbits up. Over some weeks, the thin air takes of its energy. Find its new height and the change in its kinetic energy. (, .)
In a circular orbit of radius : , , independent of the satellite's mass. Its energies: , , .
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Before. .
Step 2. After. , so : a height of .
Step 3. Kinetic energy. rises by .
Answer: About up; its kinetic energy rises by .
Check. The potential energy falls by twice as much, , so the total falls by .
Watch out. Drag makes a satellite speed up. It sinks into a lower orbit, where orbits are faster.
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