# Math Help - Physics Gravitational Forces

1. ## Physics Gravitational Forces

A spacecraft is orbiting around venus. The acceleration due to gravity at its orbit is 3m/s^2 . Estimate the height of the orbit above Venus' surface. Take the acceleration due to gravity at Venus's surface to be 8.87 m/s^2 and the radius of Venus to be 6050km.
How do I approach this? I tried using $g = \frac{G M}{(r+h)^2}$ but since we are not given a mass and we have 2 acceleration values, how do you "assemble" this puzzle?

2. ## Re: Physics Gravitational Forces

at h = 0

r = rv , g = 8.87. use this to find a M value

then at h = h(orbit)
r = rv
g = 3
M is what you worked out and you can find the value of h

3. ## Re: Physics Gravitational Forces

Originally Posted by infkelsier
at h = 0

r = rv , g = 8.87. use this to find a M value

then at h = h(orbit)
r = rv
g = 3
M is what you worked out and you can find the value of h
I presume that "rv" is the "radius of Venus?"

-Dan

4. ## Re: Physics Gravitational Forces

Originally Posted by topsquark
I presume that "rv" is the "radius of Venus?"

-Dan
yeh