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प्रश्न
Iqbal has to push a lighter box and Seema has to push a similar heavier box on the same floor. Who will have to apply a larger force and why?
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उत्तर
The force of friction arises because of the interlocking of irregularities on the two surfaces in contact. When a heavy object is placed on the floor, the interlocking of irregularities on the surfaces of the box and floor becomes strong. This is because the two surfaces in contact are pressed harder. Hence, more force is required to overcome the interlocking. Thus, Seema has to apply a greater force than Iqbal to push the heavier box.
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संबंधित प्रश्न
Select the correct alternative.
Friction is reduced by
Name the two kinds of forces in nature.
State two factors which directly affect the force of friction.
When you apply brakes, the bicycle stops and the rim of the wheel becomes hot? Explain the reason.
Arrange the following in descending order:
- static friction
- sliding friction and
- rolling friction?
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.
Answer the following.
What do you understand by a force?
Fill in the blank.
.................... is the SI unit of 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.
Answer the following in a word or two or in a sentence.
Which type of force acts on a string pulled from both ends?
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.
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.
Fill in the blank.
Friction depends upon the ............... of an object.
Fill in the blank.
Friction is a type of .................
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.
Rolling friction is slightly greater than sliding friction.
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 |
Assertion: We can live very happily if friction is not present in nature.
Reason: The airplane shape is streamlined to reduce the effort of frictional force.
