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प्रश्न
Whenever the surfaces in contact tend to move or move with respect to each other, the force of friction comes into play
विकल्प
only if the objects are solid.
only if one of the two objects is liquid.
only if one of the two objects is gaseous.
irrespective of whether the objects are solid, liquid or gaseous.
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उत्तर
irrespective of whether the objects are solid, liquid or gaseous.
Explanation:
Force of friction acts in solids, liquids and gases and opposes the motion with respect to each other.
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संबंधित प्रश्न
Friction depends on the ______ of surfaces.
Explain why sportsmen use shoes with spikes.
Give examples to show that friction is both a friend and a foe.
Give an example to illustrate the existence of the force of friction.
Name the three kinds of friction.
List three ways of reducing friction.
Give three examples to illustrate that friction is a necessary evil.
Define rolling friction
Fill in the blank.
.................... is the SI unit of force.
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 short.
What do you understand by normal force?
Fill in the blank.
Weight remaining the same, friction is independent of ............. of surface in contact.
Tick the most appropriate answer.
If you pour some oil onto a floor, the friction would
Fill in the blank
Rolling friction is ............. than sliding friction.
A moving body comes to rest due to friction alone.
Match the following.
| Column I | Column II | |
| a) | Static friction | viscosity |
| b) | Kinetic friction | least friction |
| c) | Rolling friction | objects are in motion |
| d) | Friction between the liquid layers | objects are sliding |
| e) | Sliding friction | objects are at rest |
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: We can live very happily if friction is not present in nature.
Reason: The airplane shape is streamlined to reduce the effort of frictional force.
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.
