Question

The weight of an object four earth radii from the center of the earth is:

A. 16 times it's weight on the surface.
B. 1/4 It's weight on the surface.
C. 4 times it's weight on the surface.
D. 1/16 It's weight on the surface.

Answer 1

D. 1/16 It's weight on the surface.

Step-by-step explanation:

As we know that the gravity due to earth at its surface is given as

`g = (GM)/(R^2)`

now at the distance of 4 radius of earth the gravity is given as

`g' = (GM)/((4R)^2)`

so we can say that

`g' = (g)/(16)`

so here gravity becomes 1/16 times of the gravity due to earth on its surface

now we know that weight on the surface of earth is given as

`W = mg`

also the weight now at the given height is given by

`W' = mg/16`

so here correct answer will be

D. 1/16 It's weight on the surface.