# Homework Help: Mars Problem

1. Apr 29, 2015

### AmericanBoy

1. The problem statement, all variables and given/known data
On Mars, a martian tells you he has 35.0kg of mass. What is his weight on mars?

Mars Info:
Mass= 6.42x10^23

2. Relevant equations
FG=GM1M2/R^2

3. The attempt at a solution
I tried using the equation above, but i got 4.28x10^13. Im pretty sure you have to find Gravity on mars and multiply it with the martians mass because mass to weight on earth is mass(kg) x 9.8 m/s^2 (Gravity on Earth)

(Hopefully this is a better format than my last thread.

2. Apr 29, 2015

### AmericanBoy

3. Apr 29, 2015

### haruspex

it sounds like you forgot to multiply by G.. please post all working.

4. Apr 29, 2015

### AmericanBoy

That's the problem. How do you find G on Mars???

5. Apr 29, 2015

### haruspex

G is a universal constant (not to be confused with g).

6. Apr 30, 2015

### CheesyPeeps

If you have a data sheet, the gravitational field strengths for various planets may be given. This would allow you to use W=mg.

7. Apr 30, 2015

### haruspex

I'm sure AmericanBoy is supposed to use the information about Mars provided.

8. Apr 30, 2015

### Staff: Mentor

How would information like this help the OP who is trying to learn the fundamentals?

Chet

9. Apr 30, 2015

### Scheuerf

It looks like you have the correct formula, you just plug everything in to get the final answer. (6.67 x 10^-11N·(m/kg)^2)(35kg)(6.42 x 10^23kg) / (3.4 x 10^6m)^2.