Q 1. What is the value of the universal gravitational constant?
Q 2. State the universal law of gravitation.
Q 3. If the distance between two point masses is doubled, then how does the force of gravity between them vary? Why?
Q 4. Where on the earth is the value of acceleration due to the earth’s gravity maximum?
Q 5. Rahul drops an iron ball from a certain height at the poles and records the time taken by it to hit the ground. He drops the same iron ball at the equator from the same height and records the time again. Does the iron ball take the same time duration to hit the ground at both the locations? Justify your answer.
Q 6. Two objects are dropped from the 3rd floor of a building. The mass of one object is three times more than the other. Which object will reach the ground first, if the air resistance is zero? Why?
Q 7. Calculate the force of gravitational attraction between two objects having masses of 40 kg and 35 kg kept 10 metres away from each other.
[Gravitational Constant G = 6.67 × 10-11 N m2 kg-2]
Q 8. To estimate the height of a bridge over a river, a stone is dropped freely from the bridge into the river. The stone takes 2 seconds to touch the water surface of the river. Calculate the height of the bridge from the water level. (g = 9.8 m/s2)
Q 9. A stone is dropped from a cliff. What will be its speed when it has fallen 100 m?
(g = 9.8 m/s2)
Q 10. a) Name the force that keeps a body moving along the circular path.
b) All the planets are moving in circular orbits. What will happen if this force disappears suddenly?
Q 11. What do you mean by weight of a body?
Q 12. Mass of body is 11.8 kg. What is its weight? (acceleration due to gravity = 9.8 m/s2)
Q 13. How much would a 70 kg man weigh on the moon? What would be his mass on the earth and on the moon? (acceleration due to gravity on the moon = 1.63 m/s2)
Q 14. Differentiate between mass and weight
Q 15. Calculate the value of the acceleration due gravity on the surface of the moon. (given: mass of the moon =7.4 x 1022 kg, radius of the moon = 1.74 x106 m, G = 6.67 × 10-11 N m2 kg-2)
Q 16. Multiple Choice Questions:
1. Weight of an object in air is 560 N. Its weight in water will be
a) Greater than 560 N
b) Less than 560 N
c) 560 N
d) Zero
2. The earth attracts an object with a force of 5000 N. With what magnitude would the object attract the earth?
a) 4000 N
b) 5000 N
c) 8000 N
d) 0 N
3. When you throw an object in the upward direction, the acceleration due to gravity experienced by the object is
a) + 9.8 m/s2
b) - 9.8 m/s2
c) zero
d) + 9.8 km/s2
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