# Centripetal force problem

## Homework Statement

While 2 astronauts were on the surface of the moon, a third astronaut orbited the moon. Assume the orbit to be circular and 100km above the surface of the moon. If the mass and radius of the moon at 7.40x10^22kg and 1.70x10^6m respectively, determine (a) the orbiting astronauts acceleration, (b) his orbital speed, and (c) the period of the orbit

## The Attempt at a Solution

I'm pretty clueless here...

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gneill
Mentor
Start with the easy bits. First collect whatever equations you think might be applicable. The question is about gravity and circular motion, so... what are the 'usual suspects' for formulas used there?

So I started doing it a bit and so far I have gotten the gravitational acceleration to be 1.71m/s^2 but from here how can I solve the actual acceleration the astronaut is experiencing without his mass?

gneill
Mentor
Show your work so far for the acceleration.

Actually I solved it haha... I had a momentary brain fart. But anyway I solved for gravity and gravity is the acceleration that the person in orbit experiences and its easy from there.

Very good