Advertisements
Advertisements
Question
Which of the following quantities remain constant in a planetary motion (consider elliptical orbits) as seen from the sun?
Options
Speed
Angular speed
Kinetic Energy
Angular momentum.
Advertisements
Solution
Angular momentum.
In planetary motion, the net external torque on the planet is zero. Therefore, angular momentum will remain constant.
APPEARS IN
RELATED QUESTIONS
Write the answer of the question with reference to laws of gravitation.
State the universal law of gravitation.
Choose the correct alternative:
Acceleration due to gravity increases/decreases with increasing depth. (assume the earth to be a sphere of uniform density).
A person brings a mass of 1 kg from infinity to a point A. Initially the mass was at rest but it moves at a speed of 2 m s −1 as it reaches A. The work done by the person on the mass is −3 J. The potential at A is
Three equal masses m are placed at the three corners of an equilateral triangle of side a. Find the force exerted by this system on another particle of mass m placed at (a) the mid-point of a side, (b) at the centre of the triangle.
A tunnel is dug along a diameter of the earth. Find the force on a particle of mass m placed in the tunnel at a distance x from the centre.
A solid sphere of mass m and radius r is placed inside a hollow thin spherical shell of mass M and radius R as shown in the following figure . A particle of mass m' is placed on the line joining the two centres at a distance x from the point of contact of the sphere and the shell. Find the magnitude of the resultant gravitational force on this particle due to the sphere and the shell if (a) r < x < 2r, (b) 2r < x < 2R and (c) x > 2R.
A uniform metal sphere of radius a and mass M is surrounded by a thin uniform spherical shell of equal mass and radius 4a (In the following figure). The centre of the shell falls on the surface of the inner sphere. Find the gravitational field at the points P1 and P2 shown in the figure.
State whether the gravitational force between two masses is attractive or repulsive ?
Define one Newton. How much maximum acceleration can it produce in a mass of 1 kg?
Why don't you feel the force of attraction between your friend sitting close to you and yourself?
What does a force do in the following case?
You twist a piece of rubber.
What does a force do in the following case?
You catch a kicked ball.
Two equal and opposite forces acting at the same point on a stationary body. Will the body move? Give reason to explain your answer.
Gravity is another kind of ________. It exerts all through the ________. The Sun's gravity keeps the ___________ in their orbits. Gravity can only be felt with very large ________.
Explain why:
The atmosphere does not escape.
Answer the following question.
What are the dimensions of the universal gravitational constant?
Mahendra and Virat are sitting at a distance of 1 m from each other.Their masses are 75 kg and 80 kg respectively. What is the gravitational force between them? (G = 6.67 × 10-11 Nm2/kg2)
The force of gravitation between two bodies of mass 1 kg each separated by a distance of 1 m in vacuum is ____________.
If the law of gravitation, instead of being inverse-square law, becomes an inverse-cube law- ______.
- planets will not have elliptic orbits.
- circular orbits of planets is not possible.
- projectile motion of a stone thrown by hand on the surface of the earth will be approximately parabolic.
- there will be no gravitational force inside a spherical shell of uniform density.
Observe the figure and answer the questions:
- State Newton's universal law of gravitation.
- If the distance between the two bodies is tripled, how will the gravitational force between them change?
- What will happen to gravitational force, if mass of one of the object is doubled?
