Gravitation Exercise # 2

EXERCISE # 2 Q.8. Q.1 Q.2 Q.3 Q.4 Q.5 When an apple falls from a tree: (A) only earth attracts the apple (B) only apple attracts the earth (C) both the earth and the apple attract each other (D) none attracts each other Force of attraction between two bodies does not depend upon : (A) the shape of bodies (B) the distance between their centres (C) the magnitude of their masses (D) the gravitational constant When the medium between two bodies changes, force of gravitation between them : (A) will increase (B) will decrease (C) will change according to the environment (D) remains same S.I. unit of G is : (A) Nm2 kg–2 (C) N kg2M–2 (A) 6.673 × 10–9 Nm2 kg–2 (B) 6.673 × 10–10 Nm2 kg–2 (C) 6.673 × 10–2 Nm2 kg–2 (D) 6.673 × 10–11 Nm2 kg–2 Q.9 Q.6 The value of G in S.I. unit is : (A) 6.67 × 10–9 (B) 6.67 × 10–10 –11 –12 (C) 6.67 × 10 (D) 6.67 x 10 Q.7 The gravitational force between two bodies varies with distance r as : (A) 1/r (B) 1/r2 (C) r (D) r2 Value of G on surface of earth is 6.673 × 10–11 Nm2 kg–2, then value of G on surface of Jupiter is : (A) 12 × 6.673 × 10–11 Nm2 kg–2 6.673 × 1 0–11 Nm2 kg–2 12 (C) 6.673 × 10–11 Nm2 kg–2 (B) (D) 6.673 × 10–11 Nm2 kg–2 6 Q.10 The earth attracts the moon with a gravitational force of 1020 N. Then the moon attracts the earth with a gravitational force of: (A) 10–20 N (B) 102 N (C) 1020 N (D) 1010 N Q.11 The orbits of planets around the sun are: (A) circular (B) parabolic (C) elliptical (C) straight Q.12 Law of gravitation is applicable for: (A) heavy bodies only (B) medium sized bodies only (C) small sized bodies only (D) bodies of any size Q.13 The universal law of gravitation was proposed by : (A) Copernicus (B) Newton (C) Galileo (D) Archimedes (B) Nm kg–2 (D) Nkg m–2 The value of universal gravitational constant: (A) changes with change of place (B) does not change from place to place (C) becomes more at night (D) becomes more during the day The value of G in year 1900 was 6.673 × 10–11 Nm2 kg–2, The value of G in the year 2007 will be : Q.14 Choose the correct statement : Q.20 A ball is thrown vertically upwards. The acceleration due to gravity: (A) is in the direction opposite to the direction of its motion (B) is in the same direction as the direction of its motion (C) increases as it comes down (D) become zero at the highest point. Q.21 The acceleration due to gravity on the moon's surface is: (A) approximately equal to that near the earth's surface (B) approximately six times that near the earth's surface (C) approximately one-sixth of that near the earth's surface (D) slightly greater than that near the earth's surface Q.22 The force acting on a ball due to earth has a magnitude Fb and that acting on the earth due to the ball has a magnitude Fe Then : (A) Fb = Fe (B) Fb > Fe (C) Fb < Fe (D) Fe = 0 Q.23 Force of gravitation between two bodies of mass 1 kg each kept at a distance of 1 m is : (A) 6.67 N (B) 6.67 × 10–9 N (C) 6.67 × 10–11 N (D) 6.67 × 10–7 N Q.24 The force of gravitation between two bodies does not depend on: (A) their separation (B) the product of their masses (C) the sum of their masses (D) the gravitational constant Q.25 The ratio of the value of g on the surface of moon to that on the earth's surface is : (A) All bodies repel each other in the universe. (B) Our earth does not behave like a magnet. (C) Acceleration due to gravity is 8.9 ms–2 (D) All bodies fall at the same rate in vacuum. Q.15 The value of acceleration due to gravity (g) on earth's surface is : (A) 6.67 x 10–11 Nm2 kg2 (B) 8.9 m/sec2 (C) 9.8 m/sec2 (D) none of these Q.16 The acceleration due to gravity: (A) has the same value everywhere in space (B) has the same value everywhere on the earth (C) varies with the latitude on the earth (D) is greater on moon because it has smaller diameter Q.17 Q.18 Q.19 When a space ship is at a distance of two earths radius from the centre of the earth, the gravitational acceleration is : (A) 19.6 ms–2 (B) 9.8 m/s–2 (C) 4.9 m/s2 (D) 2.45 ms–2 If planet existed whose mass and radius were both half of the earth, the acceleration due to gravity at the surface would be : (A) 19.6 m/sec2 (B) 9.8 m/s2 (C) 4.9 ms–2 (D) 2.45 m/s2 A stone is dropped from the top of a tower. Its velocity after it has fallen 20 m is [Take g = 10 ms–2] : –1 –1 (A) 5 ms (B) 10 m s (C) 15 m s–1 (D) 20 m s–1 (A) 6 1 (C) 6 (B) (D) 6 1 6 Q.26 Order of magnitude of G in S.I. unit is : (A) 10–11 (B) 1011 (C) 10–7 Q.27 (B) same as weight of an object (C) measure of gravitational pull (D) none of these (B) m/s2 (D) m/s If the distance between two masses be Q.34 1 times 4 1 (C) times 2 Q.29 Q.30 Q.31 Q.32 (B) refers to its inertia (C) same as its mass but is expressed in (B) 4 times different units (D) the force with which it is attracted towards the earth (D) 2 times The type of force which exists between charged bodies is (A) only gravitational (B) neither gravitational nor electrical (C) only electrical (D) both electrical and gravitational The acceleration due to gravity is 9.8 m/s2 (A) Much above the earth's surface (B) Near the earth's surface (C) Deep inside the earth (D) At the centre of the earth A particle is taken to a height R above the earth's surface, where R is the radius of the earth. The acceleration due to gravity there is (A) 2.45 m/s2 (B) 4.9 m/s2 (C) 9.8 m/s2 (D) 19.6 m/s2 When a body is thrown up, the force of gravity is : (A) in upward direction (B) in downward direction (C) zero (D) in horizontal direction The weight of an object is : (A) the quantity of matter it contains doubled then the force between them will become : (A) Mass of an object is : (A) amount of matter present in the object (D) 107 The S.I. unit of g is : (A) m2/s (C) s/m2 Q.28 Q. 33 Q.35 Weight of an object depends on : (A) temperature of the place (B) atmosphere of the place (C) mass of an object (D) none of these Q.36 Q.37 The mass of body is measured to be 12 kg on the earth. Its mass on moon will be : (A) 12 kg (B) 6 kg (C) 2 kg (D) 72 kg A heavy stone falls: (A) faster than a light stone (B) slower than a light stone (C) with same acceleration as light stone (D) none of these Q.38 A stone is dropped from the roof of a building takes 4s to reach the ground. The height of the building is : (A) 19.6m (B) 39.2 m (C) 156.8 m (D) 78.4 m Q.39 A ball is thrown up and attains a maximum height of 19.6 m. Its initial speed was: (A) 9.8 ms–1 (B) 44.3 ms–1 (C) 19.6 ms–1 (D) 98 ms–1 Q.40 The value of g at pole is : (A) greater than the value at the equator (B) less than the value at the equator (C) equal to the value at the equator (D) none of these Q.41 Two bodies A and B of mass 500 g and 200 g respectively are dropped near the earth's surface. Let the acceleration of A and B be aA and aB respectively, then: (A) aA = aB (B) aA > aB (C) aA< aB Q.42 A body is thrown up with a velocity of 20 m/s. The maximum height attained by it is approximately: (A) 80 m (B) 60 m (C) 40 m (D) 20 m Q.43 The weight of a body is 120 N on the earth. If it is taken to the moon, its weight will be about: (A) 120 N (B) 60 N (C) 20 N (D) 720 N Q.44 Two iron and wooden balls identical in size are released from the same height in vacuum. The time taken by them to reach the ground are(A) not equal (B) exactly equal (C) regularly equal (D) zero (D) aA aB ANSWER KEY EXERCISE-2 Ques Ans Ques Ans Ques Ans 1 C 16 C 31 A 2 A 17 D 32 B 3 D 18 A 33 A 4 A 19 D 34 D 5 B 20 A 35 C 6 C 21 C 36 A 7 B 22 A 37 C 8 D 23 C 38 D 9 C 24 C 39 C 10 C 25 C 40 A 11 C 26 A 41 A 12 D 27 B 42 D 13 B 28 A 43 C 14 D 29 D 44 B 15 C 30 B