# Homework Help: Gravity on other planets

1. Jan 24, 2005

### Gogsey

The planet Zond 4(made up) has a mass which is one third the mass of the earth, and a radius which is one quarter of the earth's radius.

What is the accelerationdue to gravityon the surface of Zond 4?

Thanks

2. Jan 24, 2005

### clive

Don't you think is better to turn over your physics book before you post? What you need for this problem is a very, very elementary equation. Search your book and give us some equations you find appropriate for this problem. After that we'll find a solution!

3. Jan 24, 2005

### DB

If you are doing this for the sake of physics , and don't have the textbooks (otherwise you might have posted on the homework threads), then I'll give you a start.

The gravitational field strengh equation

$$E_{g.field}=4\pi G \frac{m}{4\pi r^2}$$

Use kilograms and meters and plug in the numbers.

4. Jan 24, 2005

### cepheid

Staff Emeritus
Well of course he is! Didn't you hear about the recent discovery of the planet Zond 4? :rofl:

5. Jan 25, 2005

### DB

Haha, yes of course!