Question

A planet revolves in an elliptical orbital around the sun. The kinetic energy of the planet will be maximum at

A. A
B. B
C. C
D. D

Answer 1

Correct Answer - D
Conservation of angular momentum
`I_(1)omega_(1)=I_(2)omega_(2) " " therefore MR_(1)^(2)omega_(1)=MR_(2)^(2)omega_(2)`
`therefore R_(1)^(2)(V_(1))/(R_(1))=R_(2)^(2)(V_(2))/(R_(2)) " " therefore V_(1)R_(1)=V_(2)R_(2)`
At D, R is minimum `" " therefore` V is maximum.
`therefore` K.E. is maximum.