Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
A satellite orbits above the Earth. Find its kinetic, potential and total energies, and the energy it would need to escape. (, .)
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. : .
Step 2. and .
Step 3. To escape. It needs : more.
Answer: , , ; escape needs .
Watch out. The escape energy from orbit equals the kinetic energy it already has.
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