A planet is revolving round the sun in an elliptical orbit as shown in figure. Select correct alternative(s)

Options

A. Its total energy is negative at D.
B. Its angular momentum is constant
C. Net torque on the planet about sun is zero
D. Linear mementum of the planet is conserved

Answer

A, B, C

Explanation

For (A) : For a bound system, the total energy is always negative.
For (B) : For central force field, angular momentum is always conserved.
For ( C ) : For central force field, torque = 0.
For (D) : In presence of external force, linear momentum is not conserved.