Problems Based on Class 9 Science Chapter 10 Gravitation

Q.1. An object weighs 10N when measured on the surface of the earth. What would be its weight when measured on the surface of the Moon?

Q.2. Mass of an object is 10kg. What is its weight on Earth?

Q.3. What is the mass of an object whose weight is 49N?

Q.4. A body has a weight of 10 kg on the surface of earth. What will be its mass and weight when taken to the centre of earth?

Q.5. An object is thrown vertically upwards and rises to a height of 10m. Calculate (i) the velocity with which the object was thrown upwards and (ii) the time taken by the object to reach the highest point.

Q.6. A stone drops from the edge of a roof. It passes a window 2m high in 0.1s. How far is the roof above the top of the window?

Q.7. Calculate the force of gravity acting on your friend of mass 60kg. Given mass of earth = 6 x 10²⁴ kg and radius of Earth = 6.4 x 10⁶m.

Q.8. A force of 20N acts upon a body weight is 9.8N. What is the mass of the body and how much is its acceleration?

Q.9. If a planet existed whose mass was twice that of Earth and whose radius 3 times greater, how much will a 1kg mass weigh on the planet?

Q.10. A boy on cliff 49m high drops a stone. One second later, he throws a second stone after the first. They both hit the ground at the same time. With what speed did he throw the second stone?

Q.11. A stone is dropped from the edge of a roof. (a) How long does it take to fall 4.9m ? (b) How fast does it move at the end of that fall? (c) How fast does it move at the end of 7.9m? (d) What is its acceleration after 1s and after 2s?

Q.12. How much would a 70 kg man weigh on moon? What will be his mass on earth and moon? Given g on moon = 1.7 m/s².

Q.13. The Earth’s gravitational force causes an acceleration of 5 m/s² in a 1 kg mass somewhere in space. How much will the acceleration of a 3 kg mass be at the same place?

Q.14. A force of 2 kg wt. acts on a body of mass 4.9kg. Calculate its acceleration.

Q.15. A particle is thrown up vertically with a velocity of 50m/s. What will be its velocity at the highest point of the journey? How high would the particle rise? What time would it take to reach the highest point? Take g = 10 m/s².

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