Which of the following graphs represents the relationship between the orbital velocity $(v_o)$ of a satellite and its distance $(r)$ from the center of the Earth?

The centripetal force acting on a satellite orbiting around the Earth and the gravitational force of the Earth acting on the satellite are both equal to $F$. The net force on the satellite is

Assertion $A$: An astronaut inside a massive spaceship orbiting around the Earth will experience a finite but small gravitational force.
Reason $R$: The centripetal force necessary to keep the spaceship in orbit around the Earth is provided by the gravitational force between the Earth and the spaceship.

In the case of an orbiting satellite,if the radius of the orbit is decreased,then:

If the gravitational force between two objects is proportional to $1/R$,where $R$ is the distance between the two objects,then the orbital speed $v$ is proportional to which of the following?

Imagine a light planet revolving around a very massive star in a circular orbit of radius $R$ with a period of revolution $T$. If the gravitational force of attraction between the planet and the star is proportional to $R^{-5/2}$,then,