MCQ on Friction Class 8
Choose the correct answer.
Question 1.
The frictional force exerted by fluids is called
A) rolling friction
B) sliding friction
C) drag
D) normal force
Answer:
C) drag
Question 2.
___________ reduce the frictions
A) Lubricants
B) Drag
C) Mass
D) None of these
Answer:
A) Lubricants
Question 3.
The change in the length of a spring is ___________ to the applied force.
A) Indirect proportional
B) Equal
C) Direct proportional
D) Not depend on the force
Answer:
C) Direct proportional
Question 4.
The bodies of birds and fishes must have evolved to shapes which would make them not to loose much energy in overcoming ___________ friction.
A) Rolling
B) Static
C) Sliding
D) Fluid
Answer:
D) Fluid
Question 5.
Which of the following friction has self adjusting force ?
A) Sliding friction
B) Static friction
C) Rolling friction
D) Fluid friction
Answer:
B) Static friction
Question 6.
Friction is independent of ___________
A) Nature of surface
B) Normal force
C) Irregularities in surface
D) Area of contact
Answer:
D) Area of contact
Question 7.
To overcome friction ___________ are used in machinery.
A) dynamo
B) motor
C) wires
D) ball bearings
Answer:
D) ball bearings
Question 8.
The friction exerted by moving body is called ___________
A) static friction
B) sliding friction
C) rolling friction
D) drag
Answer:
B) sliding friction
Question 9.
The friction acting on the body which is at rest is ___________
A) static friction
B) rolling friction
C) drag
D) sliding friction
Answer:
A) static friction
Question 10.
The friction which is least among all the frictions
A) static friction
B) sliding friction
C) rolling friction
D) drag
Answer:
C) rolling friction
Question 11.
The force which opposes to relative motion of two surfaces of the bodies which are in contact is called
A) Muscular force
B) Frictional force
C) Gravitational force
D) Magnetic force
Answer:
B) Frictional force
Question 12.
When applied force ___________ is than the limit of the static friction then the body starts to move.
A) less
B) more
C) equal
D) none of these
Answer:
B) more
Question 13.
Friction is caused by the ___________ on the two surfaces which are in contact.
i) smoothness
ii) irregularities
iii) roughness
iv) cleanliness
A) i and iv
B) ii and iii
C) iii and iv
D) all the above
Answer:
B) ii and iii
Question 14.
Because of friction ___________ of surfaces increases.
A) density
B) volume
C) temperature
D) pressure
Answer:
C) temperature
Question 15.
When one body rolls over the surface of another body, the friction offered is called ___________
A) static friction
B) sliding friction
C) drag
D) rolling friction
Answer:
D) rolling friction
Question 16.
___________ and ___________ are called fluids.
A) Liquids, gases
B) Solids, liquids
C) Solids, gases
D) Solids, moltens
Answer:
A) Liquids, gases
Question 17.
Choose suitable option for matching.
| Group A | Group B |
| 1) Static friction | a) Drag |
| 2) Sliding friction | b) Object at rest |
| 3) Rolling friction | c) Nature of surface |
| 4) Fluid friction | d) Object in motion |
| 5) Friction | e) Ball bearing |
A) 1 – a, 2 – b, 3 – c, 4 – d, 5 – e
B) 1 – b, 2 – d, 3 – e, 4 – a, 5 – c
C) 1 – d, 2 – b, 3 – e, 4 – a, 5 – c
D) 1 – d, 2 – e, 3 – b, 4 – a, 5 – c
Answer:
B) 1 – b, 2 – d, 3 – e, 4 – a, 5 – c
| Group A | Group B |
| 1) Static friction | b) Object at rest |
| 2) Sliding friction | d) Object in motion |
| 3) Rolling friction | e) Ball bearing |
| 4) Fluid friction | a) Drag |
| 5) Friction | c) Nature of surface |
Question 18.
If we rub our hands, heat is generated by
A) static friction
B) sliding friction
C) rolling friction
D) drag
Answer:
B) sliding friction
Question 19.
Assertion (A) : The force of friction is greater if a rough surface is involved.
Reason (R) : Rough surface contains a large number of irregularities.
A) A and R are true, R supports A
B) A and R are false
C) A and R are true, R does not support A
D) A is true, but R is false
Answer:
A) A and R are true, R supports A
Question 20.
In which of the following surface a ball move fastly ?
A) covered with grass
B) covered with hard cement
C) covered with sand
D) covered with saw dust
Answer:
B) covered with hard cement
Question 21.
How do you prove that friction produces heat ?
A) By rubbing your palms against each other
B) By striking a match stick against a rough surface
C) By putting iron rod in the sunlight
D) A or B
Answer:
D) A or B
Question 22.
“Don’t throw over the roads, they may cause slip” is applicable to
A) Bananas
B) oils
C) sand
D) above all
Answer:
D) above all
Question 23.
This gives to birds and fishes to overcome from drag.
A) colour of the body
B) shape of the body
C) mass of the body
D) above all
Answer:
B) shape of the body
Question 24.
Which of following is correct ?
A) Friction is good
B) Friction is evil
C) Both A & B
D) None
Answer:
C) Both A & B
Question 25.
In this games / sports less friction is required
A) pole jump
B) carrom board
C) running
D) wrestling
Answer:
B) carrom board
Question 26.
Ramu observed holes in a flexi banners.
A) Drag friction
B) Static friction
C) Sliding friction
D) Rolling friction
Answer:
A) Drag friction
Question 27.
Situation:
i) Flying bird in the air
ii) Swimming fish in the water
iii) Moving aeroplane in the sky
Which of the above feels fluid friction?
A) only (i)
B) only (ii)
C) only (i) and (ii)
D) (i), (ii) and (iii)
Answer:
D) (i), (ii) and (iii)
Question 28.
If we apply oil on door hinges, the friction will _________
A) increase
B) decrease
C) disappear altogether
D) will remain unchanged
Answer:
B) decrease
Question 29.
To sharpen the blade of a knife by rubbing it against a surface, which of the following will be most suitable ?
A) Stone
B) Plastic block
C) Wooden block
D) Glass block
Answer:
A) Stone
Question 30.
Which of the following statements is incorrect ?
A) Friction acts on a ball rolling along the ground
B) Friction acts on a boat moving on water
C) Friction acts on a bicycle moving on a smooth road
D) Friction does not act on a ball moving through air
Answer:
D) Friction does not act on a ball moving through air
Question 31.
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
A) spread a carpet on the wooden surface
B) cover the ball with a piece of cloth
C) sprinkle talcum powder on the wooden surface
D) sprinkle sand on the wooden surface
Answer:
C) sprinkle talcum powder on the wooden surface
Question 32.
Fluid means
A) solid and gas
B) gas and liquid
C) solid and liquid
D) solid, liquid and gas
Answer:
B) gas and liquid
Question 33.
The frictional force exerted by fluids is also called ………………
A) rolling friction
B) static friction
C) drag
D) above all
Answer:
C) drag
Question 34.
Drag exerts in
A) solids
B) gases
C) liquids
D) B and C
Answer:
D) B and C
Question 35.
All vehicles are designed to have shapes which reduce …………………
A) Rolling friction
B) Static friction
C) Drag
D) Above all
Answer:
C) Drag
Question 36.
Adjacent activity is example for
A) Produce of heat by friction
B) Reduce ofifriction
C) Effect of rollers of friction
D) None
Answer:
A) Produce of heat by friction
Question 37.
Drag is not observed in
A) a
B) b
C) c
D) d
Answer:
D) d
Question 38.
To reduce friction between rotating shafts of machine tools, we use
A) Carbon powder
B) Sand
C) Powder
D) Ball bearings
Answer:
D) Ball bearings
Question 39.
The purpose of Powder while playing carroms is ………………..
A) to decrease friction
B) to increase friction
C) either to decrease or to increase of friction
D) keep the friction as constant
Answer:
A) to decrease friction
Question 40.
Situations:
i. Flying bird in the air
ii. Swimming fish in the water
iii. Moving aeroplane in the sky
Which of the above feels fluid friction?
A) only (i)
B) only (ii)
C) only (i) and (ii)
D) (i), (ii) and (iii)
Answer:
D) (i), (ii) and (iii)
Question 41.
Assertion (A) : A ball is moving fast on smooth surface than rough surface even you apply same force on it.
Reason (R) : Force of friction is greater on a rough surface.
A) Both Assertion and Reason are correct and “R” is wrong explanation for “A”.
B) Assertion is correct and Reason is incorrect.
C) Both Assertion and Reasons are wrong.
D) Both Assertion and Reasons are correct and “R” is correct explanation for Assertion.
Answer:
D) Both Assertion and Reasons are correct and “R” is correct explanation for Assertion.
Question 42.
Assertion (A): Rollers are fitted to suitcase to pull easily.
Reason (R): It is always difficult to roll a body than to slide it over a surface.
A) Both Assertion and Reason are correct and Reason is wrong explanation.
B) Assertion is correct, Reason is incorrect.
C) Both Assertion and Reasons are incorrect.
D) Both Assertion and Reasons are correct and Reason is correct explanation.
Answer:
B) Assertion is correct, Reason is incorrect.
Question 43.
Why are Aeroplanes constructed as shown in figure ?
A) To overcome fluid friction
B) To overcome rolling friction
C) To overcome static friction
D) To overcome sliding friction
Answer:
A) To overcome fluid friction
Question 44.
Which of the following is incorrect in the case of friction ?
A) Frictional force is dependent of the area of contact.
B) Friction is proportional to the normal force.
C) Friction opposes the relative motion between two surfaces in contact.
D) Friction opposes the motion of a body.
Answer:
A) Frictional force is dependent of the area of contact.
Question 45.
Hypothesis : The sole of shoe’s grave is to provide better grip on the floor.
Reason : Friction is caused by the irregularities on the two surface those are in contact.
A) Hypothesis is correct. Reason is correct explanation of hypothesis.
B) Hypothesis is correct. Reason is not correct explanation of hypothesis
C) Hypothesis is not correct and reasons are correct
D) Both hypothesis and reasons are not correct
Answer:
A) Hypothesis is correct. Reason is correct explanation of hypothesis.
Question 46.
Which of the following represents the correct sequence of types of friction arranged on based on their strength or magnitude ?
A) Static friction < sliding friction < rolling friction
B) Rolling friction < sliding friction < static friction
C) Sliding friction < rolling friction < static friction
D) Rolling friction < static friction < sliding friction
Answer:
B) Rolling friction < sliding friction < static friction
Question 47.
Abhay is playing on a rough slide. He slides down with some difficulty. Which of these stops him from sliding down smoothly ?
A) Gravity
B) Friction
C) Abhay’s weight
D) Sand at the bottom of the slide
Answer:
B) Friction
Question 48.
A box is being pulled across a rough floor at a constant speed. What can you say about the work done by friction ?
A) Friction does negative work
B) Friction does no work at all
C) Friction does positive work
D) Cannot be determined
Answer:
A) Friction does negative work
Question 49.
Oiling the chain of a bicycle makes it run smoother. Why does this happen?
A) The oil increases the friction between the gear cogs and the chain making them turn more easily.
B) The oil decreases the friction between the gear cogs and the chain by acting as a lubricant making them turn more easily.
C) The oil decreases the friction by making the gear cogs contact and the chain links expand.
D) The oil increases the friction by keeping the gear cogs and the chain cool.
Answer:
B) The oil decreases the friction between the gear cogs and the chain by acting as a lubricant making them turn more easily.
Question 50.
Akash is playing on a rough slide. He slides down with some difficulty. Which of these stops him from sliding down smoothly ?
A) gravity
B) friction
C) Akash’s weight
D) sand at the bottom of the slide
Answer:
B) friction
Diagram based bits :
Question 51.
What type of friction is acting in the given figure ?
A) Static friction
B) Sliding friction
C) Rolling friction
D) Drag
Answer:
C) Rolling friction
Question 52.
What type of friction is acting in the given figure ?
A) Static friction
B) Sliding friction
C) Rolling friction
D) Drag
Answer:
B) Sliding friction
Question 53.
What type of friction will exert by the object in the given figure ?
A) Static friction
B) Sliding friction
C) Rolling friction
D) Drag
Answer:
C) Rolling friction
Fill in the blanks.
1. ……………………. opposes the relative motion between two surfaces in contact.
Answer:
Friction
2. Friction acts on ……………………. the surfaces.
Answer:
both
3. Friction depends on ……………………. in contact.
Answer:
the nature of surfaces
4. For a given pair of surfaces friction depends upon the state of ……………………. of those surfaces.
Answer:
smoothness
5. Friction depends on how hard the two surfaces ……………………. .
Answer:
press together
6. ……………………. friction comes into play when we try to move an object at rest.
Answer:
Static
7. ……………………. friction comes into play when an object is sliding over another.
Answer:
Sliding
8. Sliding friction is ……………………. than static friction.
Answer:
smaller
9. ……………………. is important for many of our activities.
Answer:
Friction
10. Friction can be increased by making a surface ……………………. .
Answer:
rough
11. The sole of the shoes and the tyres of the vehicle are treaded to ……………………. friction.
Answer:
increase
12. Friction is sometimes ……………………. .
Answer:
undesirable
13. Friction can be reduced by applying ……………………. .
Answer:
lubricants
14. When one body rolls over another body, ……………………. friction comes into play.
Answer:
rolling
15. Rolling friction is ……………………. than sliding friction.
Answer:
smaller
16. In many machines, friction is reduced by using ……………………. .
Answer:
ballbearings
17. ……………………. friction can be minimised by giving suitable shapes to bodies moving in fluids.
Answer:
Fluid
18. Friction is a type of ……………………. force.
Answer:
Contact
Match the following.
Question 1.
| Group – A | Group – B |
| P) Rolling friction | i) breaks |
| Q) Sliding friction | ii) pushing a vehicle at rest |
| iii) ball bearings |
Answer:
P – iii, Q – i
| Group – A | Group – B |
| P) Rolling friction | iii) ball bearings |
| Q) Sliding friction | i) breaks |
Question 2.
| Group – A | Group – B |
| P) Wheels | i) sliding friction |
| Q) Air | ii) rolling friction |
| iii) fluid friction |
Answer:
P – ii, Q – iii
| Group – A | Group – B |
| P) Wheels | ii) rolling friction |
| Q) Air | iii) fluid friction |
Question 3.
| Group – A | Group – B |
| P) Friction is an evil | i) writing on a board |
| Q) Friction is a friend | ii) wears the machine |
| iii) smooth surface |
Answer:
P – i, Q – iii
| Group – A | Group – B |
| P) Friction is an evil | i) writing on a board |
| Q) Friction is a friend | iii) smooth surface |