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GRAVITATION, , 1. For a satellite moving in an orbit around the earth, the ratio of kinetic energy to potential energy is, (a)l/2, , (o)1/v2, (cl2, (djv2, , 2. The density of a newly discovered planet is twice that of earth. The acceleration due to gravity at the, surface of the planet is equal to that at the surface of the earth. If the radius of the earth is R, the radius, of the planet would be, , (a)2R, (b)}4R, (c)R/4, (d)R/2, , 3. Two spheres of masses m and M are situated in air and the gravitational force between them is F. The, space around the masses is now filled with a liquid of specific gravity 3. The gravitational force will now, be, , (a)3F, (b)F, (c)F/3, (d)F/9, , 4. The acceleration due to gravity on the planet A is 9 times the acceleration due to gravity on planet B., Aman jumps to a height of 2m on the surface of A. What is the height of jump by the same person on, the planet B?, , (a)(2/9)m, (b)18m, (c)m, (d)(2/3)m, , 5, For a planet having mass equal to mass of the earth but radius is one fourth of radius of the earth., Then escape velocity for this planet will be, , {a)11.2 km/sec, , (b)22.4 km/sec
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(c)5.6 km/sec, , (d}44.8 km/sec., , 6. Gravitational force is required for, (a)stirring of liquid, , (b)convection, , (c)conduction, , (d)radiation., , 7. A body of weight 72 N moves from the surface of earth at a height half of the radius of earth, then, gravitational force exerted on it will be, , (a)36N, (b)32.N, , (c)144.N, (d)50 N., , 8. The escape velocity of a body on the surface of the earth is 11.2 km/s. If the earth’s mass increases to, twice its present value and radius of the earth becomes half, the escape velocity becomes, , (a)22.4 km/s, (b}44,8 km/s, (c)5.6 km/s, , (d)11.2 km/s., , 9. he period of revolution of planet A around the sun is 8 times that of B. The distance of A from the sun, is how many times greater than that of B from the sun?, , (aj4, (b)S, (c)2, (d)3, , 10. The radius of earth is about 6400 km and that of mars is 3200 km. The mass of the earth is about 10, times mass of mars. An object weighs 200 N on the surface of earth. Its weight on the surface of mars, will be, , (a)20 N, (b)8 N
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(c)80 N, (d}40 N., , 11. If the gravitational force between two objects were proportional to 1/R (and not as 1/R*), where Ris, the distance between them, then a particle in a circular path (under such a force) would have its orbital, speed v, proportional to, , (a)R, , (b}R° [independent of R}, (c)a/R, , (d)a/R., , 12. A satellite A of mass m is at a distance of r from the surface of the earth, Another satellite B of mass, 2m is at a distance of 2r from the earth’s centre. Their time periods are in the ratio of, , (a)1:2, (b):16, (c)1:32, (d)a:2v2, , 13. A satellite S is moving in an elliptical orbit around the earth. The mass of the satellite is very small, compared to the mass of the earth. Then,, , (a)the linear momentum of S remains constant in magnitude,, (b)the acceleration of $ is always directed towards the centre of the earth., , (c)the angular momentum of $ about the centre of the earth changes in direction, but its magnitude, remains constant., , (d)the total mechanical energy of S varies periodically with time., , 14, Two astronauts are floating in gravitational free space after having lost contact with their spaceship., The two will, , (a)move towards each other., , (b)move away from each other., , (c)will become stationary., , (d)keep floating at the same distance between them., , 15. If the mass of the Sun were ten times smaller and the universal gravitational constant were ten, times larger in magnitude, which of the following is not correct?, , {a)Raindrops will fall faster.
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(b)Walking on the ground would become more difficult., (c)Time period of a simple pendulum on the Earth would decrease., , (d)g on the Earth will not change.
