Question 61 : The Universal law of gravitation must apply to?
1. The earth and the moon.
2. The planets around the Sun.
3. Any pair of bodies.
4. The earth and the apple.
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Question 62 : The weight of a body in a frame of reference is equal and opposite to the force required to prevent it?
1. from providing a velocity equal to its instantaneous velocity,
2. from accelerating from rest in that frame of reference.
3. from an elastic collision
4. from increasing its momentum.
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Question 63 : The acceleration of the moon is because of the?
1. Gravitational force exerted on the earth by the moon
2. Gravitational force exerted on the moon by the earth.
3. Gravitational force exerted by the Sun.
4. Gravitational force exerted by the planets
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Question 64 : At the surface of earth an object falling freely experiences an acceleration of?
1. 9.1 ms^-2
2. 9.4 ms^-2
3. 9.6 ms^-2
4. 9.8 ms^-2
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Question 65 : The force of gravity on a body varies slightly from place to place on the earth for two reason. (i) shape of earth and (ii) ?
1. the rotation of the earth
2. the mass of the earth
3. the circumference of the earth
4. All of these
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Question 66 : The radius of earth is?
1. RE = 6.45 X 10⁶ m
2. RE = 7.45 X 10⁶ m
3. RE = 9.45 x 10⁶ m
4. RE = 6.38)< 10⁶ m
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Question 67 : g' decrease with?
1. amplitude
2. horizontal displacement
3. altitude
4. weight
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Question 68 : If the radius of the earth were to shrink and its mass were to remain the same, the acceleration due to gravity on the surface of the earth with?
1. decrease
2. zero
3. increase
4. remain the same
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Question 69 : Gravitational force is responsible for?
1. Keeping planets in their radii.
2. Keeping planets on theft axes.
3. For the motion of planets around the Sun.
4. None of these.
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Question 70 : The distance from the center of earth to the center of the moon' is called as?
1. Orbital length of the earth.
2. Orbital radius of the earth.
3. Orbital length of the moon.
4. Orbital radius of the moon.
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