# MCQ Questions for Class 8 Science Chapter 12 Friction with Answers

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## Friction Class 8 MCQs Questions with Answers

Choose the correct option.

Question 1.
Friction is a
(a) non-contact force
(b) contact force
(c) magnetic force
(d) electrostatic force

Question 2.
Which of the following produces least friction?
(a) Sliding friction
(b) Rolling friction
(c) Composite friction
(d) Static friction

Question 3.
Friction always
(a) opposes the motion
(b) helps the motion
(c) both (a) and (b)
(d) none of these

Question 4.
Friction can be reduced by using
(a) oil
(b) grease
(c) powder
(d) all of these

Question 5.
Static friction is less than
(a) sliding friction
(b) rolling friction
(c) both (a) and (b)
(d) none of these

Question 6.
Whenever the surfaces in contact tend to move or move with respect to each other, the force of friction comes into play
(a) only if the objects are solid.
(b) only if one of the two objects is liquid.
(c) only if one of the two objects is gaseous.
(d) irrespective of whether the objects are solid, liquid or gaseous.

Answer: (d) irrespective of whether the objects are solid, liquid or gaseous.

Question 7.
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

Question 8.
The shape of an aeroplane is like a
(a) dog
(b) bird
(c) car
(d) all of these

Question 9.
Friction is
(a) foe
(b) friend
(c) both (a) and (b)
(d) none of these

Answer: (c) both (a) and (b)

Question 10.
Friction due to fluids is called
(a) force
(b) pressure
(c) friction
(d) drag

Question 11.
Which of the following is not a smooth surface?
(a) Surface of wet soap
(b) Surface of tyres
(c) Glazed tiles
(d) Surface of mirror

Question 12.
A toy car released with the same initial speed will travel farthest on
(a) muddy surface
(b) polished marble surface
Cc) cemented surface
(d) brick surface

Question 13.
If we apply oil on door hinges, the friction will
(a) increase
(b) decrease
(c) disappear altogether
(d) will remain unchanged

Question 14.
Lubricant
(a) reduce friction
(b) increase friction
(c) both (a) and (b)
(d) none of these

Question 15.
Force of friction depends on
(a) roughness of surface
(b) smoothness of surface
(c) inclination of surface
(d) all of these

Question 16.
Force of friction depends on
(a) roughness of surface
(b) weight
(c) size
(d) all of these

Question 17.
Fluids are
(a) liquids
(b) gases
(c) both (a) and (b)
(d) none of these

Answer: (c) both (a) and (b)

Question 18.
Which is a streamlined object?
(a) Boats
(b) Aeroplanes
(c) Ships
(d) All of these

Question 19.
Smooth surface has
(a) less friction
(b) more friction
(c) sometimes less and sometimes more
(d) all of these

Question 20.
Which of the following is responsible for wearing out of bicycle tyres?
(a) Muscular force
(b) Magnetic force
(c) Frictional force
(d) Electrostatic force

Question 21.
Mobil oil is used in scooters and bikes for which purpose?
(a) As fuel
(b) For reducing friction
(c) For increasing friction
(d) None of the above

Question 22.
Which of the following surfaces will offer the least friction?
(a) Vinyl floor
(b) Plywood
(c) Plastic
(d) Ice

Question 23.
Least amount of friction is required in which of the following sports?
(a) Car race
(b) Football
(c) Ice skating
(d) Tug of war

Question 24.
Rolling friction is smaller than
(a) sliding friction
(b) static friction
(c) both (a) and (b)
(d) none of these

Answer: (c) both (a) and (b)

Question 25.
The force of friction acts in a direction to the direction of motion of the object.
(a) same
(b) opposite
(c) perpendicular
(d) downwards

Question 26.
The force of friction depends upon
(a) nature of surfaces in contact
(b) pressure between the two surfaces
(c) both (a) and (b)
(d) none of the above

Answer: (c) both (a) and (b)

Question 27.
When the two surfaces in contact have a very thin layer of lubricant between them, it is known as
(a) solid friction
(b) rolling friction
(c) greasy friction
(d) film friction

Question 28.
Why is it harder to move a heavy box at rest across the floor than to keep it sliding?
(a) Because static friction is greater
(b) Because kinetic friction is greater
(c) Because sliding friction is greater
(d) None of these

Answer: (a) Because static friction is greater

Question 29.
Friction can be reduced by
(a) polishing
(b) oiling
(c) use of ball bearings
(d) all of these

Question 30.
Which of the following are fluids?
(a) Gases
(b) Liquids
(c) Both gases and liquids
(d) None of these

Answer: (c) Both gases and liquids

Question 31.
Friction is a
(a) contact force
(b) non-contact force
(c) magnetic force
(d) none of these

Question 32.
The maximum value of static friction that comes into play when a body is just at the point of sliding over the surface of another body is called
(a) limiting friction
(b) rolling friction
(c) sliding friction
(d) all of these

Question 33.
What is the most common way to reduce friction?
(a) Lubrication
(b) Warning signs
(c) Eliminating the motion
(d) None of these

Question 34.
Burning of meteor in the atmosphere is due to
(a) electrostatic force
(b) magnetic force
(c) frictional force
(d) gravitational force

Question 35.
When an object moves through a liquid, it experiences
(a) static friction
(b) sliding friction
(c) fluid friction
(d) rolling friction

Fill in the Blanks

Question 1.
Sliding friction is ____________ than static friction.

Question 2.
Friction can be reduced by using ___________

Answer: oil or powder or grease

Question 3.
Friction can be increased by making surface ___________

Question 4.
Rolling friction is ___________ than sliding and static friction.

Question 5.
Friction due to fluid is also called ___________

Question 6.
Bodies of birds, fishes and ships are ___________

Question 7.
Friction can also produce ___________

Question 8.
All objects moving in fluids have __________ shape to reduce ___________

Question 9.
Rough surfaces produce __________ friction than smooth surfaces.

Question 10.
In many machines, friction is reduced by using ___________

Question 11.
Friction depends on the __________ of substances in contact.

Question 12.
Static friction comes into play when we try to move an object at ___________

Question 13.
__________ force is responsible for downward movement of a parachutist when he jumps from an air craft.

Question 14.
The sole of shoes and the tyres of vehicles are treaded to ___________ friction.

Question 15.
Friction is sometimes ___________

Question 16.
The force of friction always opposes the ……………………. force.

Question 17.
Water and other liquids exert ……………………. when objects move through them.

Question 18.
Shapes that are designed to reduce air resistance are called ……………………. shapes.

Question 19.
Rolling friction is ……………………. than sliding friction.

Question 20.
Graphite acts as a ……………………. in machinery.

Question 21.
Friction can be increased by making a surface …………………….

True or False

Question 1.
Friction is always useful to us.

Question 2.
Fluids are only liquids.

Question 3.
Friction is less for smooth surfaces.

Question 4.
A soapy floor is slippery due to increased friction.

Question 5.
Friction always works in opposite direction to the relative motion.

Question 6.
Friction is dependent on area of contact.

Question 7.
Sliding friction is less than rolling friction.

Question 8.
Friction decreases with increase in the smoothness of the surface.

Question 9.
It is easier to move a heavy object than a light object.

Question 10.
Friction can be reduced by using lubricants.

Question 11.
Friction is independent of the nature of surfaces in contact.

Question 12.
A spring balance measures force.

Question 13.
Friction can be reduced by using ball bearings in some machines.

Question 14.
Friction can never be eliminated.

Question 15.
Friction do not produce heat.

Question 16.
Rolling increases friction.

Question 17.
Friction is due to the roughness of the two surfaces in contact.

Question 18.
Rolling friction is lesser than the static friction.

Question 19.
Sliding friction is always less than static friction.

Question 20.
Fluids are only liquids in nature.

Question 21.
Soapy floor is slippery due to increased friction.

Question 22.
Smooth surface has less frictional force.

Question 23.
Streamlined shape of objects reduces friction.

Question 24.
Friction is always harmful for us.

Question 25.
Friction increases with increase in the pressure between the two surfaces in contact.

Match the following

 Column I Column II 1. Fluid friction (a) Due to friction 2. Lubricants (b) Streamlined 3. Wheels (c) Increases friction 4. Spring balance (d) Drag 5. Shape of aeroplane (e) Rolling friction 6. Rough surface force (f) Reduce friction 7. Heat generation (g) Measures force