# Gravity force on Jupiter problem

1. Sep 15, 2004

### Whatupdoc

At the surface of Jupiter's moon Io, the acceleration due to gravity is 1.81m/s^2 . A watermelon has a weight of 49.0N at the surface of the earth. In this problem, use 9.81m/s^2 for the acceleration due to gravity on earth

1.) What is its mass on the surface of Io?

2.) What is its weight on the surface of Io?

working on #1, F=m*a

F = m * 1.81

all we really know is (a) of Io. but we do know the force(49.0N) of earth, how would i convert that to the forces of Io?

2. Sep 15, 2004

### underthebridge

Your mass, my mass, mass of object x, etc. is going to be the same whether you're on the Earth, the moon, Io, etc. It is the weight that changes depending on your location's acceleration due to gravity.

As it stands you have enough info to solve for the mass of the watermelon on Earth...

3. Sep 15, 2004

### Whatupdoc

yes, but im not trying to solve for the mass of the watermelon on earth, that was another question, but i already got the answer. it's 4.99 kg

im trying to solve for the mass on the surface of Io. here's what i done:

F= m*a
49 = m*1.81
m = 27.07kg
that's the mass of Io that i got, but it's the wrong answer.

4. Sep 15, 2004

### underthebridge

And what I'm telling you is the mass of the watermelon doesn't change because it is now on Io. The weight changes because the acceleration due to gravity changes, the mass remains the same.

5. Sep 15, 2004