A satellite S is moving in an elliptical orbit around the earth. The mass of the satellite is very small compared to the mass of the earth.

Options

A. The acceleration of S is alwas directed towards the centre of the Earth
B. The angular momentum of S about the centre of the Earth changes in direction, but its magnitude remain constant
C. The total mechanical energy of S varies perodically with time
D. The linear momentum of S remains constant in magnitude

Answer

A

Explanation

Force on satellite is always towards earth, therefore, acceleration of satellite S is always directed towards centre of the earth Net torque of this gravitational force F about centre of earth is zero. Therefore, angular momentum (both in magnitude and direction) of S about centre of earth is constant throughout. Since the force F is conservative in nature, therefore mechanical energy of satellite remains constant. speed of S is maximum when it is nearest to earth and minimum when it is farthest.