Increasing and Decreasing Friction

Q. Which of the following methods can be used to increase friction between two surfaces?

1. Applying lubricant between surfaces

2. Using powder between surfaces

3. Using ball bearings
4. Making the surfaces more irregular

Q.

Four children were asked to arrange forces due to rolling, static, and sliding frictions in decreasing order. Their arrangements are given below. Choose the correct arrangement.

1. rolling, static, sliding

2. rolling, sliding, static

3. static, sliding, rolling

4. sliding, static, rolling

Q.

Why is it difficult to walk on a smooth and wet floor?

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

1. True
2. False

Q. Write some disadvantages of fluid friction.

Q.

We have two identical metal sheets. One of them is rubbed with sandpaper and the other with ordinary paper. The one rubbed with sandpaper shines more than the other. Give reason.

Q. Which of the following method can increase friction?

1. Applying lubricant.
2. Applying powder on carrom board.
3. Making shoes with spikes.
4. Adding wheels to a sliding cart.

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

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

Q.

People slip if they step on a banana peel while walking. Which of these is a possible reason?

1. Banana peel reduces friction.

2. Banana peel has no effect on friction.

3. Banana peel increases friction.

4. Banana peel first increases friction and then decreases it after sometime.

Q. Which of the following statements is incorrect?​
i) Friction acts on both liquids and gases.​
ii) Friction is only an evil. ​
iii) Fluid friction is least for streamlined objects.​

Q. Fluid friction can be reduced by:

1. using ball bearings
2. streamlining the shape of the object
3. using lubricaants
4. increasing the density of the fluid

Q. For the same pair of bodies, the correct relation between different types of friction is:

1. Static friction > Rolling friction > Sliding friction
2. Static friction > Sliding friction > Rolling friction
3. Rolling friction > Sliding friction > Static friction
4. Sliding friction > Static friction > Rolling friction

Q. How can we reduce the fluid friction?

Q. Which of the following statements is incorrect?​
i) Both liquids and gases exert pressure.​
ii) Friction is only an evil. ​
iii) fluid friction is least for streamlined objects.​

1. Only (I) and (ii)​
2. Only (ii) and (iii)​
3. Only (iii)​
4. Only (ii)​

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

1. 
2. 
3. 
4. 

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

1. ball bearings
2. grooves
3. spikes

Q. Kabaddi players rub their hands with during a match to improve the grip.

1. oil
2. grease
3. water
4. sand

Q. Treads help expel water out of the way so that tyres can grip well on wet roads.

1. True
2. False

Q. Treaded tyres help in improving grip while moving on soft surfaces.

1. False
2. True

Q. If all other factors remain same, arrange these media in increasing order of frictional force offered by them.

1. Air
2. Vacuum
3. Water
4. Honey

Q. What do you mean by fluid friction? Which factors affect fluid friction?

Q. What is the use of lubricants? Explain using an example.

Q. F1 cars don't have treaded tyres and hence cannot develop sufficient friction.

1. False
2. True

Q. Ball bearings use friction instead of sliding friction.

1. rolling
2. static
3. kinetic

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. 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