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प्रश्न
How do you feel when you touch a nail immediately after it is hammered into a wooden plank? Why?
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उत्तर
The nail becomes hot due to friction. Friction changes kinetic energy to heat.
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संबंधित प्रश्न
State two factors which directly affect the force of friction.
Arrange the following in descending order:
- static friction
- sliding friction and
- rolling friction?
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 short.
Define force. Write its SI unit.
Fill in the blank.
Weight remaining the same, friction is independent of ............. of surface in contact.
Tick the most appropriate answer.
Force of friction comes into play when a/an
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.
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: ______.
