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Gravitation CBSE Class 9

Full fledge assessment Videos

Video Based Test funda (Please watch the above videos before attempting this assessment)
Question 1/20

Q 1. A ball is dropped from a height of 20 m. It reached the ground in 2 seconds. What is the final velocity of the ball?

Solution

20 m/s

v = u + g t

g = 10 m/s2

v = 0 + 10 × 2

v = 20 m/s

Final velocity of the ball is 20 m/s.

Q 2. If the weight of an object is 20 N, then the mass of the object is

Solution

If the weight of an object is 20 N, then the mass of the object is 2 N.

W = m g

20 N = m × 10

m = 2 kg

Q 3. The unit of gravitational constant is

Solution

The unit of gravitational constant is Nm2/kg2.

Q 4. As the density of a liquid increases, the

Solution

As the density of the liquid increases, the buoyant force increases.

Q 5. Working of the hydrometer is based on

Solution

Working of the hydrometer is based on Archimedes’ principle.

Q 6. As we go above the Earth’s surface, the value of gravity ‘g’

Solution

As we go above the Earth’s surface, the value of gravity ‘g’ decreases.

Q 7. If the body is thrown vertically upwards, its velocity

Solution

If the body is thrown vertically upwards, its velocity decreases and becomes zero when it reaches its maximum height.

Q 8. The weight of an object on the Moon is _________ times the weight of an object on the Earth.

Solution

The weight of an object on the Moon is 1/6 times the weight of an object on the Earth.

Wmoon = Wearth

Q 9. Weight of a liquid displaced by an object is equal to

Solution

Weight of a liquid displaced by an object is equal to the weight of an object and buoyant force acting on an object.

Q 10. The gravitational force is inversely proportional to

Solution

The gravitational force is inversely proportional to the square of the distance between objects.

Q 11. The buoyant force will decrease if

Solution

The buoyant force will decreases if the volume of the solid object decreases and the density of the liquid decreases.

Q 12. The mass of an object on the Earth is 30 kg. Its mass on the Moon will be

Solution

The mass of an object on the Earth is 30 kg. Its mass on the Moon will be 30 kg.

Mass remains constant everywhere.

Q 13. If the density of a substance is more than water, then it will _________ the water.

Solution

If the density of a substance is more than water, then it will sink in the water.

Q 14. Gravitational force is always an ______ force.

Solution

Gravitational force is always an attractive force.

Q 15. The nail with __________ will be inserted easily inside the wooden plank.

Solution

The nail with smaller surface area will be inserted easily inside the wooden plank.

Q 16. The SI unit of thrust is

Solution

The SI unit of thrust is Newton (N).

Q 17. The value of gravitational constant is

Solution

The value of gravitational constant is 6.67 × 10-11 Nm2/kg2.

Q 18. The force acting on an object at an angle of ________ to the surface is called thrust.

Solution

The force acting on an object at an angle of 90° to the surface is called thrust.

Q 19. The SI unit of density is

Solution

The SI unit of density is kg/m3.

Q 20. The acceleration produced in a freely falling object to reach the surface of the Earth does not depend on

Solution

The acceleration produced in a freely falling object to reach the surface of the Earth does not depend on the mass of the freely falling object.

Still have doubt?

Gravitation Notes

Revision Notes

Read CBSE Class 9 Physics revision notes for Gravitation

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