(i) According to law of conservation of angular momentum L = mvr = constant, therefore the comet moves faster when it is close to the sun and moves slower when it is farther away from the sun. Therefore, the speed of the comet does not remain constant.
(ii) As the linear speed varies, the angular speed also varies.
Therefore, angular speed of the comet does not remain constant.
(iii) As no external torque is acting on the comet, therefore,
according to law of conservation of angular momentum, the angular momentum of the comet remain constant.
(iv) Kinetic energy of the comet
As the linear speed of the comet changes its kinetic energy also changes. Therefore, its KE does not remain constant.
(v) Potential energy of the comet changes as its kinetic energy changes.
(vi) Only angular momentum and total energy of a comet remain constant throughout its orbit.