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प्रश्न
Sometimes, a crackling sound is heard while taking off a sweater during winters. Explain.
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उत्तर
When we take off our sweaters in winter, we hear a crackling sound. This is because removing our sweater acquires charge due to friction between the sweater and our body. As a result, we hear a crackling sound from the sweater.
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संबंधित प्रश्न
A charged glass rod attracts a charged plastic straw.
Write true or false.
The sliding friction is more than the rolling friction.
State two factors which directly affect the force of 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 a word or two or in a sentence.
Why does a rolling ball stop after moving some distance?
Answer the following in detail.
What are the various effects of force? State one example of each.
Fill in the blank.
Weight remaining the same, friction is independent of ............. of surface in contact.
Tick the most appropriate answer.
Force of friction comes into play when a/an
Tick the most appropriate answer.
Friction for an object can be reduced by
Fill in the blank.
Friction depends upon the ............... of an object.
Fill in the blank.
Friction is a type of .................
Answer the following in short.
Define rolling friction and give an example where rolling. friction comes into play.
Answer the following in short.
List the various states of matter that offer frictional force?
Answer the following in detail.
Define friction and explain how it is useful to us.
Rolling friction is slightly greater than sliding friction.
In the following figure, a boy is shown pushing the box from right to left. The force of friction will act on the box
Analogy
Objects placed at rest on earth: ______:: Bodies slide over the surface on other body: ______.
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.
Complete the analogy.
Knot in a thread : ______ friction :: Ball bearing : ______ friction.
