# Homework Help: I need help calculating gravitational acceleration.

1. Apr 5, 2013

### GabbyOcean

1. The problem statement, all variables and given/known data

What is the acceleration of gravity on Planet X on which an object weighs 300 N if it weighs 98 N on Earth?

2. Relevant equations

My first thought was Dividing 300 N / 98 N.

3. The attempt at a solution
300 N/ 98 N = 3.06 m/s2

2. Apr 5, 2013

### SammyS

Staff Emeritus
Hello GabbyOcean. Welcome to PF !

How are weight, mass, and acceleration due to gravity related?

3. Apr 5, 2013

### GwtBc

Last edited: Apr 5, 2013
4. Apr 6, 2013

### GwtBc

I wanted to delete my post and I didn't know how, therefore I asked the moderators to erase it.What's wrong with that?

Regarding the question:

If an object weighs 98 N on Earth we have:

98/9.8 = 10 kg

Your object has a mass of 10 kg

For a 10 kg object to weigh 300 N:

300/10 = 30 N

As a Newton is the force needed to accelerate a 1 kg object 1 m s-2 in space, the gravitational acceleration on planet X is 30 m s-2

You could in fact calculate the gravitational acceleration on planet X by multiplying 9.8 by 3.06. 300/98 = 3.06 indicates that the gravitational acceleration on planet X is 3.06 times that on earth.

9.8 × 3.06 = 29.988
(the exact result of 300/98 is slightly greater than 3.06)

Last edited: Apr 6, 2013
5. Apr 6, 2013

### SammyS

Staff Emeritus
I see what happened !

I saw on my iPhone that I had a response to my first post in this thread and assumed that it was from OP (Original Poster) -- but apparently it was from you, GwtBc. Then when I got around to responding on my computer I saw the request to delete the post, but I still didn't realize that the request was from you, and not OP.

It would have been fine for you to have your post deleted, but not OK for OP, GabbyOcean, to delete the threat or an important post. (BTW: You could have deleted your post yourself.)

(I'll have to stop answering these things so late at night -- I make too many mistakes.)

In fact, you may want to delete most of your most recent post, since it give far too complete an answer.