Practice question · True or false
Gravity does no work on a satellite in a circular orbit.
Hints
- What angle does the force make with the motion?
- Work needs a component along the displacement.
Show the answer
True
Why
True. The gravitational force points to the centre while the velocity is tangential, perpendicular at every instant, so and the speed never changes. In an elliptical orbit they are not perpendicular, which is exactly why such a satellite speeds up near perigee.
Practise Energy and Conservation Laws
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