Advertisements
Advertisements
प्रश्न
Answer the following in detail.
Define friction and explain how it is useful to us.
Advertisements
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.
APPEARS IN
संबंधित प्रश्न
Name the three kinds of 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?
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.
Why does a rolling ball stop after moving some distance?
Answer the following in short.
What do you understand by normal force?
Answer the following in detail.
What are the various effects of force? State one example of each.
Answer the following in a word or two or in a sentence.
Name a method used to reduce 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 |
Is there any possibility of making a special device to measure the magnitude of friction directly?
