Question

Joe has a weight of 720 N ( about 162 lb) when he is standing on the surface of the earth . What would his weight ( the gravitational force due to the earth) be if he doubled his distance from the center of the earth by flying in space in aircraft?

Answer 1

In order to find his weight, let's analyze the formula for the gravitational force between two bodies:

$F=\frac{GMm}{d^2}$

We can see that the gravitational force is inversely proportional to the square of the distance.

So, if the distance doubles, that means the gravitational force will decrease by a factor of 4.

Joe's weight on Earth is 720 N, so his weight on the aircraft would be:

$W=\frac{720}{4}=180\text{ N}$

Joe's weight would be 180 N.