Two satellites of earth `S_(1)` and `S_(2)` are moving in the same orbit. The mass of `S_(1)` is four times the mass of `S_(2)`. Which one of the following statements is true?

Options

A. `S_(1)` and `S_(2)` are moving with the same speed
B. The kinetic energies of the two satellites are equal
C. The time period of `S_(1)` is four times that of `S_(2)`
D. The potential energies of earth and satellite in the two cases are equal

Answer

A

Explanation

When the two satellites move in the same orbit, their periods are equal. T is independent of mass. But the P.E. = mgh and K.E. `=(1)/(2)mv^(2)`, depend upon the mass. As their masses are different, their P.E. and K.E. will be different. But as they are orbiting in the same orbit, their orbital speeds are equal. Option (a) is correct.