Comets move around the sun in highly elliptical orbital. The gravitational force on the comet due to the Sun is not normal to the comets velocity in general. Yet the work done by the gravitational force over every complete orbit of the comet is zero. Why?

Open in App

Solution

Gravitational force is a conservative force. Hence the work done depends on the initial and final positions.
In a complete revolution of the sun by a comet, the displacement becomes zero, so the work done by the gravitational force over every complete orbit of the comet is zero.

Suggest Corrections

Similar questions

Answer the following :

(a) The casing of a rocket in flight burns up due to friction. At whose expense is the heat energy required for burning obtained. The rocket or the atmosphere?

(b) Comets move around the sun in highly elliptical orbits. The gravitational force on the comet due to the sun is not normal to the comets velocity in general. Yet the work done by the gravitational force over every complete orbit of the comet is zero. Why?

(c) An artificial satellite orbiting the earth in very thin atmosphere loses its energy gradually due to dissipation against atmospheric resistance, however small. Why then does its speed increase progressively as it comes closer and closer to the earth?

(d) In Figure (i) the man walks

2

m

carrying a mass of

15

k g

on his hands. In Figure (ii), he walks the same distance pulling the rope behind him. The rope goes over a pulley, and a mass of

15

k g

hangs at its other end. In which case is the work done greater?

Answer the following:

(a) The casing of a rocket in flight burns up due to friction. At whose expense is the heat energy required for burning obtained? The rocket or the atmosphere?

(b) Comets move around the sun in highly elliptical orbits. The gravitational force on the comet due to the sun is not normal to the comet’s velocity in general. Yet the work done by the gravitational force over every complete orbit of the comet is zero. Why?

(d) In Fig. 6.13(i) the man walks 2 m carrying a mass of 15 kg on his hands. In Fig. 6.13(ii), he walks the same distance pulling the rope behind him. The rope goes over a pulley, and a mass of 15 kg hangs at its other end. In which case is the work done greater?

Fig. 6.13

Q. A comet orbits Sun in a highly elliptical orbit. The comet has a constant

Q. Comets revolve around the Sun in long elliptical orbits.

Q. Consider a planet moving in an elliptical orbit around the Sun. The work done on the planet by the gravitational force of the Sun.

Join BYJU'S Learning Program

Comets move around the sun in highly elliptical orbital. The gravitational force on the comet due to the Sun is not normal to the comets velocity in general. Yet the work done by the gravitational force over every complete orbit of the comet is zero. Why?

Gravitational force is a conservative force. Hence the work done depends on the initial and final positions.In a complete revolution of the sun by a comet, the displacement becomes zero, so the work done by the gravitational force over every complete orbit of the comet is zero.

Gravitational force is a conservative force. Hence the work done depends on the initial and final positions.
In a complete revolution of the sun by a comet, the displacement becomes zero, so the work done by the gravitational force over every complete orbit of the comet is zero.