Question

A satellite, orbiting around the earth, is moved from one circular orbit to another orbit of lesser radius. Which of the following statement is true ?

• A. The kinetic energy of satellite increases and the gravitational potential energy of satellite-earth system increases;
• B. The kinetic energy of satellite increases and the gravitational potential energy of satellite-earth system decreases;
• C. The kinetic energy of satellite decreases and the gravitational potential energy of satellite-earth system decreases;
• D. The kinetic energy of satellite decreases and the gravitational potential energy of satellite-earth system increases.

Answer 1

The correct option is B The kinetic energy of satellite increases and the gravitational potential energy of satellite-earth system decreases;

In the circular motion around the Earth, the centripetal force on the satellite is a gravitational force. Therefore, $v^2=GM/R$, where M is the mass of the Earth, R is the radius of the orbit of satellite and G is the universal gravitational constant.Therefore, the kinetic energy increases with the decrease in the radius of the orbit. The gravitational potential energy is negative and decreases with the decrease in radius.