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| Previous Year Questions of March Examinations from 2010 to 2020 |
| Chapter Name: GRAVITATION |
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Weight of the body depends directly on ‘g’. Value of ‘g’ depends on many factors like the shape of the earth, rotation of earth etc. a) Choose the correct alternative i) ‘g’ increases / decreases with the incresing altitude. ii) ‘g’ is independent of the mass of earth/mass of the body iii) ‘g’ is maximum / minimum at the poles iv) ‘g’ increases / decreases with the incresing depth b) State Newtons’s law of Gravitation. Then write the unit of the Gravitational constant c) Derive the expression for orbital and escape velocity |
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A person in an artificial satellite of the. earth experiences weightlessness The moon is a natural satellite of the earth. a) Can a person on the moon experience weight? Why? b) A satellite is revolving very close to earth. What is the percentage increase in velocity needed to make it escape from the gravitational field of the earth? c) Acceleration due to gravity ‘g’ depends on the distance ‘r’ from the center of the earth. Draw a graph showing the variation of ‘g’ with ‘r’. |
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a) The value of acceleration due to gravity is maximum at the................. i. Poles ii. Equator iii. Center of the earth b) Find the height at which ‘g’ is reduced to g/2. c) A rat and a horse are to be projected from earth into space. State whether the velocity is the same or different in projecting each animal. Justify. |
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The escape speed for an object from the earth is 11.2 km/s. a) What is mean by escape speed? b) Arrive at an expression for the escape speed from the earth. c) Explain whether the escape speed depends on the mass of the object or not. d) The earth contains an atmosphere while the moon does not. Give the reason. |
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The acceleration due to gravity (g) on the surface of the earth is 9.8 ms-2 . a) Define the acceleration due to gravity (g). b) Derive an expression for the variation of g at a depth ‘d’ below the surface of earth. c) At what height ‘h’ will the value of ‘g’ be half of that on the surface of the earth? |
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Choose the correct alternative.
a) Escape velocity is independent of the mass of the earth / the mass of the body. b) Gravitational force / weak nuclear force is the weakest fundamental force. |
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Earth satellites are objects which revolve around the earth. Consider a satellite at a height ‘h’ from the surface of the earth a) Give an equation for its orbital velocity. b) Obtain an equation for the period of the above satellite. c) Distinguish between geo stationary satellites and polar satellites. |
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The value of acceleration due to gravity is maximum on the surface of the earth. a) Write the relation between acceleration due to gravity and gravitational constant. b) Obtain an equation for the variation of ‘g’ with height c) Draw a graph showing the variation of ‘g’ with depth and height from the surface of the earth. Assume that the density of earth is constant. |
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Our earth has several artificial satellites. But the moon is the only natural satellite. a) If acceleration due to gravity at the surface of earth is ‘g’, arrive at the expression for acceleration due to gravity at a depth ‘d’. b) Distance to the moon from the earth is 3.84 x 108 m and the time period of the moon’s revolution is 27.3 days. Obtain the mass of the earth. (Gravitational constant g=6.67 x 10-11 Nm2kg-2) c) How do you explain weightlessness in an artificial satellite? |
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The acceleration due to gravity may vary with altitude and depth. a) Arrive at an expression for acceleration due to gravity at a height h. (h << RE ) b) Why does satellite need no fuel to go around a planet in its fixed orbit? c) Acceleration due to gravity is independent of ................ (mass of earth / mass of body) |
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For a particle to overcome the gravitational pull of earth, it is projected with a minimum velocity. a) Name the minimum velocity. b) Obtain an expression for the above minimum velocity. c) A ball bounces more on the surface of the moon than on the earth. Explain why ? |
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a) The escape speed from the surface of the earth is given by ............ i) sqrt(2gRE) ii) sqrt(gRE) iii) sqrt(3gRE) iv) sqrt(g2RE) b) An artificial satellite circulating the earth is at a height 3400 km from the surface of the earth. If the radius of the earth is 6400 km and g = 9.8 m/s2 , calculate the orbital velocity of the satellite. |
| If the zero of potential energy is at infinity, the total energy of an orbiting satellite is negative of its ............ energy |
| Derive an expression for the escape velocity of an object from the surface of a planet |
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Acceleration due to gravity decreases with depth a) Prove the above statement by deriving proper equation b) Using the equation, show that acceleration due to gravity is maximum at the surface and zero at the center of the earth |
| Derive an expression for escape speed from a Planet |
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Earth satellites are objects which revolve around the earth a) Time period of a geostationary satellite is ........... b) Derive an expression for the time period of a satellite c) By using the expression you derived above, show that motion of satellite obeys Kepler”s law of period |
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The escape speed of an object from the earth is 11.2 km/s. (a) Define escape speed of an object. (b) How escape speed is related to the mass of the object ? |
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(a) Choose the correct alternative : (i) Acceleration due to gravity increases/decreases with increasing altitude. (ii) Acceleration due to gravity increases/decreases with increasing depth. (iii) The total energy of an orbiting satellite is negative of its kinetic/potential energy. (iv) The polar satellite go around the earth in a north-south direction/east-west direction. (b) State Kepler’s law of time periods |
| Derive an expression for acceleration due to gravity at any point above the surface of earth. |
