what would be the weight of the missile at that altitude?

A missile weighing 400N on the earth’s surface is shot into the atmosphere to an altitude of 6.4 x 10^−6m. Taking the earth as a sphere of radius 6.4 x 10^−6m and assuming the inverse-square law of universal gravitation, what would be the weight of the missile at that altitude?

A. 100N
B. 200N
C. 400N
D. 800N
E. 1600N

Correct Answer:

Option A – 100N

Explanation

W=mg/4=400/4 = 100N