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प्रश्न
Answer the following in detail.
Define friction and explain how it is useful to us.
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उत्तर
Friction is a force that opposes relative motion between two bodies/surfaces in contact with each other. Although friction opposes the motion, it also makes motion possible.
Friction helps us do many things like :
- It helps us in walking. In the absence of friction, we may slip or M.
- Cars and buses are able to move safely on roads due to the friction between the treaded tires of these vehicles and the surface of the road.
- Friction allows us to hold objects with our hands.
- It allows us to write on paper.
- Friction produces heat. In winter, when we rub our cold hands, the heat produced due to friction makes our hands warm.
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संबंधित प्रश्न
Arrange the following in descending order:
- static friction
- sliding friction and
- rolling friction?
Fill in the blank.
Rolling friction offers ............. resistance 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 has no relation with our walking or running.
Answer the following in detail.
Describe three different ways by which friction can be increased to help us in various situations?
Why is a ball bearing used in a cycle hub?
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.
Friction depends on the ______ of two surfaces in contact.
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.
Complete the analogy.
Knot in a thread : ______ friction :: Ball bearing : ______ friction.
