physics help 3!! **
posted by kelsey .
Based on the following data about planet X (which orbits around the Sun):
Planet X's distance from Sun = 3.6*1012 m
Planet X's radius = 2*106 m
Planet X's mass = 8.2*1022 kg
a.) Find gx, the size of the acceleration due to gravity on the surface of Planet X. m/s2
b.) What is the weight of a 10 kg mass on the surface of Planet X? N
(How does this compare to its weight on Earth?)
c.) How long would it take for a ball dropped from a height of 8 m to hit the ground? s
(How does this compare to the time it would take on Earth?)
d.) At 3 of Planet X's radii above the planet's surface, what is gx? m/s2
e.) Find the orbital speed of Planet X around the Sun. m/s
f.) How long is a year on Planet X? Express your answers in both seconds and Earth years:
s
Earth years

I will be glad to critique your work. We are not a homework performing service. Here are some comments to get you started.
a) gx = GM/R^2, where R is the planet's radius. G was explained in one of my previous answers.
You won't need to know the distance from the sun until you get to e) and f)