मराठी

Give examples to show that friction is both a friend and a foe.

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प्रश्न

Give examples to show that friction is both a friend and a foe.

थोडक्यात उत्तर
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उत्तर

Examples to show that friction is a friend:

  1. Friction enables us to grip and catch various objects.
  2. It allows us to walk pleasantly on the surface.
  3. It helps reduce the speed of moving items.
  4. It will enable us to write on paper or blackboards.
  5. Friction prevents objects from moving from their original positions.

Examples to show that friction is a foe:

  1. Friction wears and tears items.
  2. It damages machine parts.
  3. Machines and tools require constant maintenance, which wastes a lot of money.
  4. It slows down moving objects, requiring more significant force.
  5. It prohibits the free movement of items.
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Force of Friction
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पाठ 9: Friction - Exercises [पृष्ठ १२१]

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एनसीईआरटी Science [English] Class 8
पाठ 9 Friction
Exercises | Q 9. | पृष्ठ १२१

संबंधित प्रश्‍न

Iqbal has to push a lighter box and Seema has to push a similar heavier box on the same floor. Who will have to apply a larger force and why?


Write true or false.

Liquids offer more friction than the gases.


Name the two kinds of forces in nature.


Define static friction


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.


Fill in the blank.

Rolling friction offers ............. resistance than sliding friction.


Fill in the blank.

Weight remaining the same, friction is independent of ............. of surface in contact.


Tick the most appropriate answer

Friction always


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 a word or two or in a sentence.

Why is difficult for a pen to leave a mark on a highly smooth plastic sheet?


Answer the following in short.

Define rolling friction and give an example where rolling. friction comes into play.


Explain how friction can be minimized.


Whenever the surfaces in contact tend to move or move with respect to each other, the force of friction comes into play



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.


Assertion: There is a danger of a vehicle skidding on a wet road.
Reason: The tires of the vehicle lose their grip on the road due to an increase in friction due to the presence of water on the road.


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