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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.
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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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संबंधित प्रश्न
Give examples to show that friction is both a friend and a foe.
A charged glass rod attracts a charged plastic straw.
Name the two kinds of forces in nature.
State two factors which directly affect the force of friction.
Define rolling friction
Arrange the following in descending order:
- static friction
- sliding friction and
- rolling friction?
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.
Fill in the blank.
Sliding friction and rolling friction are types of .................. friction.
Tick the most appropriate answer.
Friction is offered by
Fill in the blank
Rolling friction is ............. than sliding friction.
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 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?
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 |
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
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.
