physics
posted by Boniface .
If the earth acceleration due to gravity on a mass of 2000kg on the earth surface is 10ms.What will be the acceleration due to gravity when it is at a point twice the radius of the earth.What is the gravitational force on it.

F = G M1 M2/r^2
G, M1 and M2 are the same, only r changes
so in this problem
F = k/r^2
r2 = 2 r1
F1 = k/r1^1 = m g = 20,000N
F2 = k/r2^2 = k/4r1^2
F2/F1 = 1/4
F2 = 2000 * 10/4 = 5,000 N
F2 = m g2
5,000 = 2,000 g2
g2 = 2.5 m/s^2