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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.
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
What is the cause of friction?
Define static friction
Define sliding friction
Answer the following.
What do you understand by a force?
State if the following statement is true or false. Correct the statement if it is false.
If two forces acting in opposite directions on a body arc of equal magnitude, then the body will not move.
State if the following statement is true or false. Correct the statement if it is false.
Like charges always attract each other.
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 short.
Define force. Write its SI unit.
Fill in the blank.
The force of friction acting between two bodies in contact while at rest is known as ................ friction.
Fill in the blank.
Friction depends upon the ............... of an object.
Fill in the blank.
Friction is a type of .................
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.
How can sliding friction be changed into rolling friction easily?
Answer the following in short.
List the various states of matter that offer frictional force?
Answer the following in detail.
Write the characteristics of the force of friction?
Answer the following in detail.
Describe three different ways by which friction can be increased to help us in various situations?
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 |
In 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.
Complete the analogy.
Knot in a thread : ______ friction :: Ball bearing : ______ friction.
