Distance from the center of the earth.?

Question

(a) Find the distance from the center of the Earth at which a 10.0 kg object has a weight of 7.0 N.
m
(b) If the object is released at this location and allowed to fall toward the Earth, what is its initial acceleration?
m/s

Answer 1

Newton's Law of Gravity is

F = G m1 m2 / r^2

where G is the gravity constant, m1 the mass of the Earth, m2 the mass of the object, and r the distance between the object and the center of the earth.

You know F = 7.0 N and m2 = 10.0 kg. Look up the mass of the Earth and the gravity constant and solve for r.

You can get the initial acceleration from the information you already have: F = ma so 7.0 N = (10.0 kg) (a)