Advantages and Disadvantages of Friction

Q.

Applying oil to machine parts increases the efficiency of the machine.

1. Towards left

2. Towards right

Q. We use ball bearings between the hub and axle of ceiling fan. Why?

Q.

What is friction? Why do we have such a hard time slipping on a rainy day?

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

1. Polishing
2. Powder
3. Oil
4. Spikes

Q.

Simple sentences....

Advantages and disadvantages of friction....

Easily ......

Q.

A rougher surface will have

1. Same friction as compared to a smoother one.

2. Less friction as compared to a smoother one.

3. Higher friction as compared to a smoother one.

4. No friction.

5. Higher friction as compared to a smoother one.

Q.

A nail becomes warm when hammered into a plank. Explain, why?

Q. ntA block of mass m is projected horizontally on a conveyer belt of lenght Lon two small rollers moving at speedv . Find the speed with which the block is projected so that the heat dissipated against friction will be maximum.n

Q.

Write down two disadvantages of friction and suggest ways to overcome these.

Q. Answer the following questions:

A. Why do we slip on a recently mopped floor?

B. Alida runs her toy car on dry marble floor, wet marble floor, newspaper and towel spread on the floor. The force of friction acting on the car on different surfaces in increasing order will be
(a) wet marble floor, dry marble floor, newspaper and towel.
(b) newspaper, towel, dry marble floor, wet marble floor.
(c) towel, newspaper, dry marble floor, wet marble floor
(d) wet marble floor, dry marble floor, towel, newspaper [5 MARKS]

Q. Give examples to show that friction is a friend or a foe.

Q.

Give reason for the following

During winter, we can warm our hands by rubbing them together.

Q.

Which of the following options represents the positive effects of friction?

1. It helps us write

2. It produces heat in running machines

3. It produces noise

4. It helps us walk

Q.

In which of the following case is friction useful?

1. Heating of an electric fan.

2. Production of noise in machines.

3. Wear and tear of shoes.

4. Use of a chalk for writing.

Q. Which of the following statement(s) is/are correct?
Statement 1: Bicycle tyres wear out due to high muscular force.
Statement 2: Treads in a tyre are made to increase the grip with the surface.

1. Only statement 1 is correct.
2. Only statement 2 is correct.
3. Both the statements are correct.
4. Both the statements are incorrect.

Q.

Which of the following methods can increase friction?

1. Applying lubricant

2. Applying powder on carrom board

3. Making shoes with spikes

4. None of these

Q.

Mention three methods by which we can reduce friction between two bodies.
[3 MARKS]

Q.

A man sharpens his knife. Which of these statements describes the properties of friction that are observed in the situation?
A. Friction helps to induce magnetism
B. Friction acts in the opposite direction of relative motion.
C. Friction causes the surfaces in contact to wear away.
D. Friction produces heat energy.

1. A & B

2. A, C & D

3. C & D

4. B, C, D

Q. Polishing a surface in contact _______.

1. increases friction
2. reduces friction
3. may increase or decrease friction
4. does not affect the amount of friction

Q.

The force of friction is_________on wet surfaces.

Q. You spill a bucket of soapy water on a marble floor accidently. Would it be easier or more difficult for you to walk on the floor now? Why?

Q.

You spill a bucket of soapy water on a marble floor accidently. Would it make it easier or more difficult for you to walk on the floor? Why?

Q. Polishing a surface in contact _______.

1. may increase or decrease friction
2. increases friction
3. does not affect the amount of friction
4. reduces friction

Q.

What would be the impact on friction if powder is sprinkled on the ?

1. It doesn't change

2. It increase little

3. It increases to a large extent

4. It decreases

Q.

Why is having treads on tires undesirable for racing cars (like the Formula1 cars)?

1. Treads decrease friction always

2. Treads increases friction always

3. Tyres cannot take advantage of the plowing effect on hard roads

4. Tyres take advantage of the plowing effect on hard roads

Q.

When the brake of a train is applied, it slows down. Which of the following force is responsible for it?

1. Heat into Kinetic energy

2. Potential energy into heat

3. Heat into potential energy

4. Kinetic energy into heat

Q.

State two advantages and two disadvantages of friction.

Q.

Why Can we write with a fountain pen without friction?

Q.

A nail becomes hot when hammered in a plank:

1. the potential energy of hammer changes into heat energy

2. the kinetic energy of the hammer changes into heat energy

3. the force of friction changes into heat energy

4. none of the above

Q.

Which of the following statements is incorrect?

1. Friction opposes relative motion of objects.

2. Friction produces heat.

3. Friction can stop a moving object.

4. Friction is never useful

5. Friction is never useful