Advertisements
Advertisements
प्रश्न
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.
उत्तर
When a book slides on the writing desk, a frictional force acts between the book and the surface of the desk. The direction of the frictional force on the book is opposite to the direction of its motion and acts upward, as shown in the following figure.
APPEARS IN
संबंधित प्रश्न
Friction opposes the ______ between the surfaces in contact with each other.
Friction depends on the ______ of surfaces.
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?
When a glass rod is rubbed with a piece of silk cloth the rod ______.
Sometimes, a crackling sound is heard while taking off a sweater during winters. Explain.
Write true or false.
Liquids offer more friction than the gases.
Select the correct alternative.
Friction is reduced by
Name the two kinds of forces in nature.
What is the cause 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.
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.
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
Tick the most appropriate answer
Friction always
Fill in the blank.
Friction is a type of .................
Answer the following in detail.
Describe three different ways by which friction can be increased to help us in various situations?
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 |
How do you feel when you touch a nail immediately after it is hammered into a wooden plank? Why?
Whenever the surfaces in contact tend to move or move with respect to each other, the force of friction comes into play
