# Physics (Circular Motion)

1. Sep 29, 2004

### Blassemer

Ok,

How do I go about finding the Force of Gravity(N) in a circular motion problem.

My teacher is asking us to solve for that, so wat do I multiply to get that?

All I need is the formula to find Force of Gravity (N).

PS. I need it pretty quick because the Homework is do tomorrow.

Thanks.

2. Sep 29, 2004

### Pyrrhus

the force of gravity? are you talking about a vertical circular motion?

3. Sep 29, 2004

### Blassemer

Here is my problem.....

It is about the planets and orbiting the sun, this is the planet earth

Radius=1.496x10^11
Period (years) = 1
Period (seconds)=31,536,000
Velocity=2.981x10^4
Centripetal Acceleration-5.94x10^-3
Force of Gravity (N)= ?
Mass (KG)=?
Centipetal Force (N)=?

I actually need to solve for those 3 things, if someone could give me the answer to those then that would be great because I have to do 8 other planets after this one so it would get me off to a good start, Thanks

if not the answer then a formula or something to find them (I really need to know how to find the Force of Gravity (N))

4. Sep 29, 2004

### Adrian Baker

The centripetal force (mv^2/r) is supplied by Gravity F=Gmm/r^2

Sun mass = 2 x 10^30 kg if I remember correctly...

5. Sep 29, 2004

### Blassemer

So, what does Gmm represent, I know r is radius but wat does Gmm mean

6. Sep 29, 2004

### Pyrrhus

Constant of Gravity (NOT 9.8 m/s^2) and m1 and m2, are the masses of the two objects.

Last edited: Sep 29, 2004
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