Suppose an earth satellite, revolving in a circular orbit experiences a resistance due to cosmic dust. Then

Options

A. its kinetic energy will increase
B. its potential energy will decrease
C. it will spiral towards the earth and in the process its angular momentum will remain conserved
D. it will burn off ultimately

Answer

A, B, D

Explanation

If a satellite is revolving in a circular orbit then the magnitude of its `KE` is equal to half of the magnitude of negative. That is why the total energy of a revolving satellite is negative. If the satellite experiences resistance due to cosmic dust, then it follows a spiral path of decreasing radius. During the process of motion, its potential energy decreases. It means `PE` becomes more negative or the magnitude of `PE` increases Hence, magnitude of `KE` also increases. Therefore, optioins a and b are correct.
Since cosmic dust exerts a tangential force on the satellite, therefore it experiences a retarding moment, hence, its angular momentum does not remain conserved. Hence option c in incorrect. Since `KE` increases. Power acting against the resisting force is equal to force `xx` speed, therefore it increases. Hence, thermal power generated increases with time. Hence, ultimately it will turn off. Therefore option d is correct.