CBSE Class 11 Physics Gravitation Notes Set A

Gravitation

 Main Points

Answer the following questions. Each question carries 1 mark

1.  State Newton’s law of Gravitation 

2.  Write the SI unit of Gravitational constant. Also give its dimensional formula

3.  What is the effect of mediumon the value of G?

4.  Define gravitational potential.

5.  Name the physical quantity whose dimensional formula is same as that of the gravitational potential. 

6.  Define gravitational potential energy.

7.  Define Orbital velocity.

8.  Define escape velocity. Give its value for the earth.

9.  What is the value of gravitational potential energy at infinity?

10. What do you mean by the earth’s satellite?

11. Write an expression for the escape velocity of a body from the surface of the earth. Also give the factors on which it depends,

12. What does a low value of escape velocity indicates?

13. What is the period of the moon?

14. What is geocentric theory? Who propounded it? 

15. What is geostationary satellite? Is it same as synchronous satellite?

16. What is heliocentrictheory? Whopropounded it?

17. StateKepler’s laws of planetary motion.

18. Name the force that provides the necessary centripetal force for a planet to move around the sunin a nearly circular  orbit. 

19. Does speed increase, decrease, or remain constant when a planet comes closer to the sun?

20. Where does a body weigh more near the poles or the equator? Why?

21. The value of G on the earth is 6.7 X 10-11Nm-2kg-2.What is its value on the moon?

Answer the following questions. Each question carries 2 marks.

1.  Give the differences between weight and mass

2.  You can shield a charge from electrical forces by putting it inside a hollow conductor. Can you shield a body from the gravitational influence of nearby matter by putting it inside a hollow sphere or by some other means?

3.  An astronaut inside a small space-ship orbiting around the Earth has a large size. Can he hope to detect gravity?

4.  The mass and diameter of a planet have twice the value of the corresponding parameters of the earth. What is the acceleration due to gravity on the surface of the planet?

5. The planet earth is revolving in an elliptical orbit around sun as shown in the fig. At what point on the orbit will the kinetic energy be (i) minimum (ii) maximum?

6. Does a rocket really need the escape velocity of 11.2km/s initially to escape from the earth? Plot a graph showing the variation of gravitational force (F) with square of the distance, Plot a graph showing the variation of acceleration due to gravity with height or depth.

7. Two planets A and B have their radii in a ratio ‘r’. The ratio of the acceleration due to gravity on the planets is’ x’. What is the ratio of the escape velocity from the two planets?

8. Write formula for the variation of g with (i) height above the surface of the earth (ii) depth below the surface of the earth (iii) rotation of the earth.

9. Give the differences between inertial mass and gravitational mass.

10. Does the escape velocity of a body from the earth depend on :

(i) The mass of the body,

(ii) The location from where it is projected,

(iii) The direction of projection,

(iv) The height of the location from where the body is launched.

Please refer to attached file for CBSE Class 11 Physics notes - Gravitation