Hey there! Sign in to join this conversationNew here? Join for free
 You are Here: Home >< Physics

# Need help with physics question? watch

1. Ok so I need to find the distance of moon from the earth using this equation > T = 4pi^2r^3/GM all in square root. I have input the G and M values but what is r and how do I find it? The question is below if anyone can help me!

Where G is the gravitational constant = 6.67x10-11 Nm^2kg^-2
M is the mass of the planet (kg) and r is the distance from the centre of the planet to the centre of
the satellite (m).
If the moon takes 27.3 days to orbit the Earth, use the equation to calculate its
distance from the Earth if the mass of the Earth is 5.975x10^24 kg.

2. has to be in seconds:

Rearrange into formula for and solve it.

(Original post by mrpopodopalaus)
r is the distance from the centre of the planet and satellite (m)

Reply
Submit reply
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: April 11, 2016
Today on TSR

### Struggling to get going with your revision?

Get going with the all day revision thread

### Uni strikes! How do they affect you?

Discussions on TSR

• Latest
Poll
Discussions on TSR

• Latest

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.