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प्रश्न
Fill in the blank.
Bicycles use ...................... to reduce friction between the pedals and the crank
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उत्तर
Bicycles use ball bearings to reduce friction between the pedals and the crank.
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संबंधित प्रश्न
When a glass rod is rubbed with a piece of silk cloth the rod ______.
When you apply brakes, the bicycle stops and the rim of the wheel becomes hot? Explain the reason.
List three ways of reducing friction.
A body needs a force F1 just to start moving on a surface, a force F2 to continue its motion and a force F3 to roll on the surface. What is
- the static friction
- sliding friction and
- rolling friction? State whether F2 is equal, less than or greater than (1) F1 and (2) F3.
Fill in the blank.
.................... is the SI unit of force.
Answer the following in short.
What do you understand by normal force?
Fill in the blank.
Weight remaining the same, friction is independent of ............. of surface in contact.
Answer the following in detail.
Define friction and explain how it is useful to us.
Complete the analogy.
Knot in a thread : _____ friction : : Ball bearing : _____ friction
Assertion: Friction always opposes the motion.
Reason: Whenever one surface moves or tries to move over another surface, the force of friction starts acting on the surfaces.
