A ball is dropped from a satellite revolving around the earth at a height of 120 km. The ball will

CONCEPT:

Orbital Velocity of Satellite:

• Satellites are natural or artificial bodies describing an orbit around a planet under its gravitational attraction.
• Orbital velocity of a satellite is the velocity required to put the satellite into its orbit around the earth.
• For the revolution of a satellite around the earth, the gravitational pull provides the required centripetal force.
• For the revolution of a satellite around the earth, the gravitational pull provides the required centripetal force.

\(\Rightarrow v = \sqrt {\frac{{GM}}{r}}\)  

Where G = universal gravitational constant, M = mass of the earth, r = distance between the earth and the satellite, and v = velocity of the satellite.

EXPLANATION:

• Orbital velocity of the satellite is given by

\(\Rightarrow v = \sqrt {\frac{{GM}}{r}}\)

• From the above equation, it is clear that the orbital velocity of the satellite is independent of the mass of the satellite. 
• Speed of the ball will be the same as that of the satellite, so when the ball is dropped from a satellite revolving around the earth at height of 120 Km, it will continue to move with the same speed along the original orbit of the satellite. Therefore option 2 is correct.