Kindly solve Q 5

For a planetary system, perihelion is the shortest distance and aphelion of the farthest distance from the star.

In simple words, a star is huge in size and mass. The centre of gravity of a planet and a star lies quite near to the star itself.

Now, work done is positive when gravitational force and displacement have same direction, if they have different directions the work done is negative.

With respect to centre of mass, perihelion is much more closer than aphelion. So, the work done is negative in both cases. But due the difference in displacement (aphelion>perihelion), the work done is more negative in case of aphelion than the work done in perihelion.

Net work done favours more negatively to aphelion. So work done from perihelion to aphelion is negative.