Chapter 9: Gravitation — Online MCQ Test
SCIENCE · CLASS 9th · Karnataka State Board
Practice Chapter 9: Gravitation with a free chapter-wise online MCQ test.
This chapter covers: This chapter covers Universal Law of Gravitation free fall acceleration due to gravity mass weight thrust pressure Archimedes principle and buoyancy..
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Chapter 9: Gravitation — Important Questions & Answers
Which force keeps the planets in orbit around the Sun?
- A. Magnetic force
- B. Gravitational force
- C. Frictional force
- D. Electrostatic force
Answer: B. Gravitational force
The Sun and planets attract each other due to gravitational force. This force provides the necessary centripetal force for orbital motion.
The Sun and planets attract each other due to gravitational force. This force provides the necessary centripetal force for orbital motion.
The SI unit of force is:
- A. Joule
- B. Watt
- C. Newton
- D. Pascal
Answer: C. Newton
Force is measured in newtons (N) in the SI system. It is the standard unit used in gravitation and mechanics.
Force is measured in newtons (N) in the SI system. It is the standard unit used in gravitation and mechanics.
Why do all bodies fall with the same acceleration in vacuum?
- A. Because all bodies have the same mass
- B. Because gravity acts equally on all bodies regardless of mass
- C. Because air resistance is absent and only gravity acts
- D. Because heavier bodies have less weight in vacuum
Answer: C. Because air resistance is absent and only gravity acts
In vacuum, there is no air resistance to slow different bodies differently. Therefore, only gravity acts and all bodies fall with the same acceleration.
In vacuum, there is no air resistance to slow different bodies differently. Therefore, only gravity acts and all bodies fall with the same acceleration.
A body is fully immersed in water. The apparent loss in its weight is equal to:
- A. The mass of water displaced
- B. The volume of water displaced
- C. The buoyant force acting on it
- D. The pressure of water on the body
Answer: C. The buoyant force acting on it
The apparent loss of weight in a fluid is due to the upward buoyant force. This buoyant force equals the weight of the fluid displaced.
The apparent loss of weight in a fluid is due to the upward buoyant force. This buoyant force equals the weight of the fluid displaced.
A block of wood floats in water. Which statement best explains this?
- A. The density of wood is greater than the density of water
- B. The buoyant force on the wood is greater than its weight
- C. The weight of the wood equals the buoyant force when it floats
- D. Gravity does not act on the wood in water
Answer: C. The weight of the wood equals the buoyant force when it floats
A floating object stays in equilibrium when its weight is balanced by the buoyant force. That is why the block remains partially immersed.
A floating object stays in equilibrium when its weight is balanced by the buoyant force. That is why the block remains partially immersed.