CBSE Class 11 Physics Gravitation Worksheet Set F

TOPIC :GRAVITATION

SECTION – A CONCEPTUAL AND APPLICATION TYPE QUESTIONS

1. 13. Why weight of a body becomes zero at the centre of earth ?

2. 14. Can a pendulum vibrate in an artificial satellite ?

3. 15. Imagine a spacecraft going from the earth to the moon . How does its weight vary as it goes from the earth ?

4. Difference between gravitational potential and gravitational field.

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

6 17. The gravitational potential energy of a body at a point in gravitational field of another body is GMm/r . What does the negative sign indicate ?

7. State Kepler’s Laws of Planetary motion .

8. Write two salient features of escape velocity ?

9. 18. The escape velocity of a body when projected from earth’s surface is 11.2 km/s. If it is projected at an angle of 500 from the horizontal , what will be the escape velocity ?

10. Name two factors which determine whether a planet would have an atmosphere or not ?

11. What is Geosynchronous satellite ?

12. What is a parking orbit ?

13. Two artificial satellites are revolving around the earth , one closer to its surface and the other away from it . Which has larger speed ?

14. The gravitational potential energy of a body at a point in gravitational field of another body is GMm/r . What does the negative sign indicate ?

SECTION – B NUMERICAL PROBLEMS

1. Find the percentage decrease in weight of a body when taken to a height of 32km abovethe surface of earth , R = 6400 km.

2. At what height above the surface of the earth does the acceleration due to gravity reduce to 64 % of its value on the surface of the earth . R = 6400 km.

3. 15. How much below the surface of the earth does the acceleration due to gravity become1 % of its value at earth’s surface ?

4. 16. A body weighs 63 N on the surface of the earth. What is the gravitational force on it due to the earth at a height equal to half the radius of the earth ?

5. Assuming the earth to be a sphere of uniform mass density, how much would a body weigh half way down to the centre of the earth if it weighed 250 N on the surface?

6. Find the potential energy of a system of four particles of equal masses M placed at the corners of a square of side L. Also obtain potential at the centre of the square.

7. A rocket is fired from the earth towards the sun. At what point on its path is the gravitational force on the rocket zero? Mass of sun = 2x 1030kg, mass of the earth = 6x10²⁴kg. Neglect the effect of other planets etc. Orbital radius = 1.5x 10¹¹m.

8. A Saturn year is 29.5 times the earth year. How far is the Saturn from the sun if the earth is 1.5 x 10⁸km away from the sun?

9. The escape velocity of a projectile on earth’s surface is 11.2 kms^-1. A body is projected out with thrice this speed. What is the speed of the body far away from the earth? Ignore the presence of the sun other planets.

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