Advertisements
Advertisements
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?
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.
APPEARS IN
संबंधित प्रश्न
Friction opposes the ______ between the surfaces in contact with each other.
Give examples to show that friction is both a friend and a foe.
When a glass rod is rubbed with a piece of silk cloth the rod ______.
Name the two kinds of forces in nature.
Define static 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?
Answer the following in a word or two or in a sentence.
Which type of force acts on a string pulled from both ends?
Answer the following in short.
What do you understand by normal force?
Fill in the blank.
More the roughness of a surface, greater is the ........................
Fill in the blank.
Smoother the surface, ................. is the frictional force offered by it.
Fill in the blank.
Friction depends upon the ............... of an object.
State if the following statement is true or false. Correct the statement if it is false.
Friction is offered by all the three states of matter.
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.
Write the characteristics of the force of friction?
A moving body comes to rest due to friction alone.
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 figure, a boy is shown pushing the box from right to left. The force of friction will act on the box
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.
Analogy
Objects placed at rest on earth: ______:: Bodies slide over the surface on other body: ______.
