Q. 26

# Out of aphelion and perihelion, where is the speed of the earth more and why?

Answer :

Aphelion is the positon of earth from where it has the greatest distance from the sun and perihelion is the position from where it has the shortest distance. Now since the angular momentum of earth about the sun is conserved then we have:

Where m is the mass of the earth, r_{ap} is the earth - sun distance at the aphelion and r_{pe} is the earth - sun distance at the perihelion.

Since r_{ap} > r_{pe}, v_{pe} > v_{ap}, therefore the velocity at the perihelion is greater than the velocity at the aphelion.

Rate this question :

The moon takes about 27.3 days to revolve round the earth in a nearly circular orbit of radius 3.84 × 10^{5} Km. Calculate the mass of the earth from these data.

The time taken by the Mars to revolve round the sun is 1.88 years. Find the ratio of average distance between Mars and the sun to that between the earth and the sun.

HC Verma - Concepts of Physics Part 1A satellite of mass 1000 kg is supposed to orbit the earth at a height of 2000 Km above the earth’s surface. Find

(a) Its speed in the orbit.

(b) Its kinetic energy.

(c) The potential energy of the earth-satellite system and

(d) Its time period. Mass of the earth = 6 × 10^{24} Kg.

HC Verma - Concepts of Physics Part 1

What is the direction of areal velocity of the earth around the sun?

Physics - ExemplarA Saturn year is 29.5 times the earth year. How far is the Saturn from the sun if the earth is 1.50 × 10^{8} km away from the sun?

The radius of planet is R_{1} and a satellite revolves round it in a circle of radius R_{2}. The time period of revolution is T. Find the acceleration due to the gravitation of the planet at its surface.

Which of the following quantities remain constant in a planetary motion (Consider elliptical orbits) as seen from the sun.

HC Verma - Concepts of Physics Part 1