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प्रश्न
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?
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उत्तर
Because the smooth surface has very less friction.
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संबंधित प्रश्न
Friction opposes the ______ between the surfaces in contact with each other.
Suppose your writing desk is tilted a little. A book kept on it starts sliding down. Show the direction of frictional force acting on it.
Explain why sportsmen use shoes with spikes.
Give three examples to illustrate that friction is a necessary evil.
A body needs a force F1 just to start moving on a surface, a force F2 to continue its motion and a force F3 to roll on the surface. What is
- the static friction
- sliding friction and
- rolling friction? State whether F2 is equal, less than or greater than (1) F1 and (2) F3.
Tick the most appropriate answer.
Friction for an object can be reduced by
Answer the following in short.
When you push something heavy, the resistance you feel decreases as soon as the object starts moving. Explain the reason.
Answer the following in detail.
Define friction and explain how it is useful to us.
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 the following figure, a boy is shown pushing the box from right to left. The force of friction will act on the box
