How to Decrease Friction

Q.

How does lubrication reduce friction.

Q. Can we reduce friction to zero by polishing surfaces or using large amount of lubricants ?

Q. Ball bearings are used in machines as friction which is than sliding friction.

1. fluid
2. rolling
3. static
4. less
5. more

Q. Question 25
Two friends are trying to push a heavy load as shown in figure. Suggest a way which will make this task easier for them.

Q. Moving parts of most machines use to reduce friction.

1. ball bearings
2. grooves
3. spikes

Q.

Which of these substances help us to reduce friction between the surfaces?

1. Using oil

2. Using fine powder

3. Both of these

4. None of these

Q.

state two examples for reducing friction while playing carrom board is helpful

Q. Pulling a suitcase with rollers is easier than pulling a suitcase without rollers.

1. False
2. True

Q. When a hockey player hits the ball passed by another player to him with the hockey stick, it can change:

1. direction of motion of the ball
2. speed of the ball
3. both direction of motion and speed of the ball
4. shape of the ball

Q.

Why is water spilled purposely on the slides in water parks? [2 MARKS]

Q.

What would be the impact on friction if a powder is sprinkled on the surface of the carrom board?

Q.

Though it is difficult to push a heavy box, the task becomes easier when wheels are attached to it.

Q.

Give the reason for the following: Steel axles of machines are made to run in brass sockets or bearings.

Q. How does the normal force acting on the body affect friction?

Q.

Which of the following is not a cause of friction?

1. Interlocking irregularities of the surface
2. Bond formation
3. Area of contact of surface
4. Surface Roughness

Q. Moving parts of most machines use to reduce friction.

1. ball bearings
2. grooves
3. spikes

Q. You have two suitcases. First suitcase is of 5 N weight and with rollers and second suitcase is of 2 N but without rollers. Now you are pulling two suitcases. Which one has less friction?

1. 
   1st suitcase has less friction
2. 
   2nd suitcase has less friction
3. 
   Both the suitcases have the same friction
4. The frictional force of the suitcases cannot be compared

Q.

How is friction between coins and carrom board affected when some powder is sprinkled on the carrom board?

1. It increases to a large extent

2. It increases little

3. It doesn't change

4. It decreases

Q. You spill a bucket of soapy water on a marble floor accidentally. Would it make it easier or more difficult for you to walk on the floor? Why?
[3 marks]
[APSCERT]
[Lubrication]

Q. Ball bearings are used in machines as friction which is than sliding friction.

1. fluid
2. rolling
3. static
4. less
5. more

Q.

Define Rolling friction

Q. m1 and m2 are two blocks placed one above other. There is no friction between the lower block and ground. The lower block is being pushed by a constant horizontal force F. There is sufficient friction between the blocks so that they dont slip over each other. Find the work done by friction on upper block from ground frame as the arrangement moves through S.

Q.

When a lubricant is applied between two surfaces, the movement becomes smooth as the interlocking of irregularities is avoided to a great extent.

1. False

2. True

Q. Choose the part which is common in all and helps to reduce friction.

1. 
2. 
3. 
4. 

Q. Ball bearings are used in machines as friction which is than sliding friction.

1. fluid
2. rolling
3. static
4. less
5. more

Q. Why carrom board is usually powdered before playing?

1. For decreasing friction.
2. For increasing friction.
3. For fragrance.
4. For decoration.

Q. If we apply oil on door hinges, the friction will ___.

1. increase
2. decrease
3. disappear altogether
4. will remain unchanged

Q. Which of the following help reduce friction between two surfaces?

1. Ball bearings
2. Polishing
3. Oil
4. Powder
5. Grease
6. Spikes
7. Sand
8. Wheels

Q. A boy rolls a rubber ball on a wooden surface. The ball travels a short distance before coming to rest. To make the same ball travel longer distance before coming to rest, he may _________.

1. spread a carpet on the wooden surface.
2. cover the ball with a piece of cloth.
3. sprinkle fine powder on the wooden surface.
4. sprinkle sand on the wooden surface.

Q. Adding more wheels to a car will decrease the frictional force on the car.

1. True
2. False