physics 12
posted by roy on .
If the Earth has a mass of 5.98*10^24 kg and orbits the Sun at a radius of 1.43*10^11 meters. Find the mass of the Sun.
Thank you.

Gravity force = centripetal force
G M m/R^2 = m V^2/R
V = 2 pi R/P
P = 1 year ( in seconds) is the period of the earth's orbit = 3.154*10^7 s
G = the universal constant of gravity
(Look it up)
m (the Earth's mass) cancels out. Solve for the solar mass, M.
M = R*V^2/G = 4*pi^2*R^3/(G*P^2)