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#### Gravitation Model Questions

11th Standard

Reg.No. :
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Physics

Time : 01:00:00 Hrs
Total Marks : 50
5 x 1 = 5
1. The time period of a satellite orbiting Earth in a cirular orbit is independent of.

(a)

(b)

The mass of the satellite

(c)

Both the mass and radius of the orbit

(d)

Neither the mass nor the radius of its orbit

2. According to Kepler’s second law, the radial vector to a planet from the Sun sweeps out equal areas in equal intervals of time. This law is a consequence of

(a)

conservation of linear momentum

(b)

conservation of angular momentum

(c)

conservation of energy

(d)

conservation of kinetic energy

3. If the mass and radius of the Earth are both doubled, then the acceleration due to gravity g'

(a)

remains same

(b)

${g\over 2}$

(c)

2g

(d)

4g

4. A body projected electrically from the earth reaches a height equal to earth's radius before returning to the earth: The power exerted by the gravitational force is greatest

(a)

at the highest position of the body

(b)

at the instant just before the body hits the earth

(c)

it remains constant all through

(d)

at the instant just after the body is projected

5. If the acceleration due to gravity at the surface of the earth is g, the work done in slowly lifting a body of mass in from the earth's surface to a height R equal to the radius of the earth is

(a)

$\frac { 1 }{ 2 }$ MgR

(b)

2 MgR

(c)

$\frac { 1 }{ 4 }$ MgR

(d)

Mg R

6. 5 x 2 = 10
7. State Kepler’s three laws.

8. Define gravitational potential energy.

9. Calculate the change in g value in your district of Tamilnadu. (Hint: Get the latitude of your district of Tamilnadu from the Google). What is the difference in g values at Chennai and Kanyakumari?

10. If the force of gravity acts on all bodies in proportion to their masses, why does heavy body not all faster than a light body?

11. Acceleration to Newton's law of gravitation the apple and the earth experience equal & opposite forces due to gravitation. But it is the apple falls towards the earth and not vice-versa. Why?

12. 5 x 3 = 15
13. A student was asked a question ‘why are there summer and winter for us? He replied as ‘since Earth is orbiting in an elliptical orbit, when the Earth is very far away from the Sun(aphelion) there will be winter, when the Earth is nearer to the Sun(perihelion) there will be winter’. Is this answer correct? If not, what is the correct explanation for the occurrence of summer and winter?

14. Obtain an expression for Gravitational Field intensity measured with an object of unit mass.

15. When does the work done to be negative and positive?

16. A geostationary satellite is orbiting the earth at a height of 5R above the surface of the earth, R being the radius of the earth. Find the time period of another satellite at a height of 2R from the surface of the earth.

17. A mass M is broken into two parts, on & (M-m). How is m related to M so that the gravitational force between two parts is maximum?

18. 4 x 5 = 20
19. Derive an expression for escape speed.

20. Explain the freely falling apple on Earth using the concept of gravitational potential V(r)?

21. Drive the relation between g & Gravitational constant.

22. Moon and an apple are accelerated by the same gravitational force due to Earth. Compare the acceleration of the two