# Forces & Fields HELP

1. Feb 11, 2007

### natural

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

Forces & Fields
Calculate the acceleration of the earth in its orbit around the sun and the net force exerted on the Earth.what exerts this force on the earth? Assume that the Earth's Orbit is a circle of radius 1.49*10^11m.
2. Relevant equations
g=GMm/r2
1 year=3.16*10^7
mass of the earth = 5.98*10^24kg
radius of the earth = 6.37*10^6m.
3. The attempt at a solution
I was approaching the question by using the equ. v2(v squared)/r.
but velocity is unknown and the distance between the sun and the earth.

2. Feb 11, 2007

### Ja4Coltrane

It's easy to find the speed--it's just distance per unit time.

3. Feb 11, 2007

### Staff: Mentor

Consider that the magnitude of average velocity (i.e. speed) can be taken as the quotient of distance travelled (orbital circumference) divided by the time (orbital period).

4. Feb 11, 2007

### natural

But neither the radius or the diameter was was given :| i wa thinking along that line but we dont have that information. is there any other way or is that the only way?

5. Feb 11, 2007