Question 251: Gravitation

Question

An astronaut of mass m is working on a satellite orbiting the earth at a distance h from the earth’s surface. The radius of the earth is R, while its mass is M. The gravitational pull F
G
on the astronaut is :

Accepted Answer

The gravitional pull on the astronaut is,
F
G
=  $${{GMm} \over {{{\left( {R + h} \right)}^2}}}$$
The satellite is moving so fast around the earth that whenever it trying to fall on the earch it is missing the earth and it will keep going arround the earth. On the satellite the astronaut feels weightless because the satellite is constantly freefalling.
If gravity were absent, the satellite would move in a straight line through space instead of orbiting the Earth. In this scenario, the astronaut would still feel weightless, but for a different reason: there would be no gravitational force acting on the satellite in the absence of gravity.
Option B : $ 0 < F_G < \frac{GMm}{R^2} $
The gravitational force $ F_G $ acting on the astronaut while in orbit is less than the gravitational force at the Earth's surface, but it is not zero. The force of gravity decreases with the square of the distance from the center of the Earth. Since the astronaut is at a distance ( R + h ) from the center of the Earth, where ( h ) is the altitude of the orbit, the gravitational force will be less than at the Earth's surface but greater than zero.
So, both
Option B
and
Option D
are correct. Option B correctly states that the gravitational force is less than at the Earth's surface but greater than zero, and Option D gives the precise formula for calculating that force.

Answer

Zero since astronaut feels weightless

Answer

0 < F
G
< $${{GMm} \over {{R^2}}}$$

Answer

$${{GMm} \over {{{\left( {R + h} \right)}^2}}}$$ < F
G
< $${{GMm} \over {{R^2}}}$$

Answer

F
G
= $${{GMm} \over {{{\left( {R + h} \right)}^2}}}$$

Gravitation

An astronaut of mass m is working on a satellite orbiting the earth at a distance h from the earth’s surface. The radius of the earth is R, while its mass is M. The gravitational pull F G on the astronaut is :

Choose the correct answer: