Gravitation Worksheet-4

Gravitation Worksheet-4

11. An object is thrown vertically upwards with a velocity u, the greatest height h to which it will rise before falling back is given by :

A. u/g                 B. u²/2g             C. u²/g                D. u/2g

12. The mass of moon is about 0.012 times that of earth of and its diameter is about h 0.25 times that of earth. The value of G on the moon will be :

A. Less than that on the earth

B. More than that on the earth

C. Same as that on the earth

D. About one-sixth of that on the earth

13. The value of g on the surface of the moon :

A. Is the same as on the earth

B. Is less than that on the earth

C. Is more than that on the earth

D. Keeps changing day by day

14. The atmosphere consisting of a large number of gases is held to the earth by :

A. Winds                                         B. Clouds

C. Earth’s magnetic field            D. Gravity

15. The force of attraction between two unit point masses separated by a unit distance is called :

A. Gravitational

B. Acceleration due to gravity

C. Gravitational field strength

D. Acceleration due to gravity

16. The weight of an object at the centre of the earth of radius R is :

A. Zero

B. R times the weight at the surface of the earth

C. Infinite

D. 1/R² times the weight at the surface of the earth

17. Two objects of different masses falling freely near the surface of moon would :

A. Have same velocity at any instant

B. Have different accelerations

C. Experience forces of same magnitude

D. Undergo a change in their inertia

18. The value of acceleration due to gravity of earth :

A. Is the same on equator and poles

B. Is the least on poles

C. Is the least on equator

D. Increases from pole to equator

19. The law of gravitation gives the gravitational force between :

A. The earth and a point mass only

B. The earth and the sun only

C. Any two bodies having some mass

D. Any two charged bodies only

20. The value of quantity G in the formula for gravitational force :

A. Depends on mass of the earth only

B. Depends on the radius of earth only

C. Depends on both mass and radius of earth

D. Depends neither on mass nor on radius of earth

Answer Key:

11. B

Explanation: Using : v² = u² + 2gh

here v = 0 ( object stops at maximum height)

g will be negative ( object is moving up)

0 = u² -2gh

So h = u²/2g

12. C

13. B

14. D

15. D

16. A

17. A

18. C

19. C

20. D