मराठी

We have two identical metal sheets. One of them is rubbed with sand paper and the other with ordinary paper. The one rubbed with sand paper shines more than the other. Give reason.

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प्रश्न

We have two identical metal sheets. One of them is rubbed with sand paper and the other with ordinary paper. The one rubbed with sand paper shines more than the other. Give reason.

कारण सांगा
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उत्तर

While rubbing with sandpaper, more frictional force is produced between the layers of metal sheet and sandpaper which causes more force on dust particles and they are removed easily, so it will shine more.

But in case of ordinary paper, the force of friction is not sufficient to remove all the dust, so it will shine less in this case.

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Force of Friction
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पाठ 12: Friction - Long Answer Questions [पृष्ठ ७२]

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एनसीईआरटी एक्झांप्लर Science Exemplar [English] Class 8
पाठ 12 Friction
Long Answer Questions | Q 23. | पृष्ठ ७२

संबंधित प्रश्‍न

Friction opposes the ______ between the surfaces in contact with each other.


Friction depends on the ______ of surfaces.


When a glass rod is rubbed with a piece of silk cloth the rod ______.


Sometimes, a crackling sound is heard while taking off a sweater during winters. Explain.


Write true or false.

Liquids offer more friction than the gases.


Define sliding friction


Arrange the following in descending order:

  1. static friction
  2. sliding friction and
  3. rolling friction?

Answer the following in a word or two or in a sentence.

Which type of force acts on a string pulled from both ends?


Answer the following in detail.

What are the various effects of force? State one example of each.


Tick the most appropriate answer.

Force of friction comes into play when a/an


Tick the most appropriate answer.

Friction is offered by


Fill in the blank.

Rolling friction is ........... than sliding friction.


Fill in the blank.

Smoother the surface, ................. is the frictional force offered by it.


State if the following statement is true or false. Correct the statement if it is false.

Friction helps us to grip the objects in our hand.


Answer the following in detail.

Describe three different ways by which friction can be increased to help us in various situations?


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


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.


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