# Gravitation Help

1. Oct 1, 2006

### Meowzers

I'm having trouble distinguishing the values of the components in the gravitation equation for the following problem:

Here is how I approached it -

The equations I will be using are:
F = G*M*m/r^2
W=KE
$$KE=\frac{1}{2}m v^2$$

So first off, I solved for the force using the gravitation equation -
G constant = 6.67e-11 Nm^2/kg^2
M (of star) = 1.14*10^32 kg
m (of rocket) = 1.25*10^6 kg
r = now this is where my question is. :yuck: The problem says that r is the distance between the centers of the two bodies. So, I assumed that it's the radius given 3.48*10^9 m added to the distance between the rocket and the star (1.85*10^11 m) and then squared. Is this correct? Or is it just supposed to be the radius of the star squared?

After that first assumption, I plugged the force value I found into
$$W=F*cos(\theta)(delta x)$$
which brings me to the second question. Is the delta x value = 1.85*10^11 m?

Then, I plugged that value I found for W into $$KE=\frac{1}{2}m v^2$$, where m=1.25*10^6.

Is this a correct approach and did I assume anything wrong?