Extra 40 multiple-choice questions (MCQs) with answers from Chapter:9 Friction for Class 8 Science (CBSE):-
What is friction?
a) A force that pulls objects downward
b) A force that opposes motion
c) A force that increases speed
d) A force that changes direction
Ans:
(b) A force that opposes motion
Friction always acts in which direction?
a) In the direction of motion
b) Opposite to the direction of motion
c) Perpendicular to the surface
d) None of these
Ans:
(b) Opposite to the direction of motion
Which of the following factors does NOT affect friction?
a) Roughness of surfaces
b) Weight of the object
c)
Colour
of the object
d) Nature of the surface
Ans:
(c)
Colour
of the object
Which type of friction is the highest?
a) Static friction
b) Sliding friction
c) Rolling friction
d) Fluid friction
Ans:
(a) Static friction
Which friction acts when an object is just about to move?
a) Static friction
b) Sliding friction
c) Rolling friction
d) Fluid friction
Ans:
(a) Static friction
Which type of friction is the least?
a) Static friction
b) Sliding friction
c) Rolling friction
d) Fluid friction
Ans:
(c) Rolling friction
Which friction helps us to walk properly?
a) Sliding friction
b) Rolling friction
c) Static friction
d) Fluid friction
Ans:
(c) Static friction
What is rolling friction?
a) Friction between two solid surfaces
b) Friction when an object rolls over a surface
c) Friction between layers of a fluid
d) None of these
Ans:
(b) Friction when an object rolls over a surface
Why is rolling friction less than sliding friction?
a) Rolling reduces the area of contact
b) Rolling increases force
c) Rolling increases friction
d) None of these
Ans:
(a) Rolling reduces the area of contact
What kind of friction do vehicles experience when moving on the road?
a) Static friction
b) Sliding friction
c) Rolling friction
d) Fluid friction
Ans:
(c) Rolling friction
Which of the following is NOT a disadvantage of friction?
a) Wear and tear of machines
b) Overheating of engines
c) Stopping of a moving vehicle
d) Extra energy consumption
Ans:
(c) Stopping of a moving vehicle
Friction is useful in which of the following activities?
a) Writing with a pen
b) Holding objects in hand
c) Walking
d) All of these
Ans:
(d) All of these
How can friction be reduced?
a) By making surfaces rough
b) By increasing contact area
c) By using lubricants
d) By pressing surfaces harder
Ans:
(c) By using lubricants
What is used in machines to reduce friction?
a) Grease
b) Oil
c) Ball bearings
d) All of these
Ans:
(d) All of these
Which force helps in holding a screw in a wall?
a) Gravity
b) Magnetism
c) Friction
d) Electrostatic force
Ans:
(c) Friction
Which force opposes the motion of objects in fluids?
a) Rolling friction
b) Sliding friction
c) Drag
d) Static friction
Ans:
(c) Drag
What helps reduce fluid friction?
a) Streamlining
b) Rough surfaces
c) Increasing surface area
d) None of these
Ans:
(a) Streamlining
Which shape is best to reduce drag?
a) Flat
b) Irregular
c) Streamlined
d) Circular
Ans:
(c) Streamlined
Which of the following animals have a streamlined body to reduce friction?
a) Birds
b) Fish
c) Both a & b
d) None of these
Ans:
(c) Both a & b
Which of these vehicles is designed to reduce air resistance?
a) A truck
b) An aeroplane
c) A bullock cart
d) A bicycle
Ans:
(b) An aeroplane
What happens to friction when weight increases?
a) Increases
b) Decreases
c) Remains same
d) Disappears
Ans:
(a) Increases
Which factor increases friction?
a) Smoother surface
b) Rougher surface
c) Lubrication
d) Ball bearings
Ans:
(b) Rougher surface
Which part of a car reduces rolling friction?
a) Engine
b) Brakes
c) Ball bearings
d) Steering wheel
Ans:
(c) Ball bearings
Which of these is NOT a way to reduce friction?
a) Lubrication
b) Polishing surfaces
c) Increasing roughness
d) Using wheels
Ans:
(c) Increasing roughness
Which of these is an example of useful friction?
a) Formation of fire by rubbing stones
b) Overheating of machines
c) Wearing out of tires
d) None of these
Ans:
(a) Formation of fire by rubbing stones
26. Friction produces:
a) Cold
b) Electricity
c) Heat
d) Light
Ans: (c) Heat
27. Friction depends on the nature of surfaces in contact.
a) True
b) False
Ans: (a) True
28. Ball bearings are used in wheels to reduce:
a) Static friction
b) Sliding friction
c) Rolling friction
d) Fluid friction
Ans: (c) Rolling friction
29. More polished surfaces have __ friction.
a) More
b) Less
c) No
d) Infinite
Ans: (b) Less
30. Without friction, we cannot __.
a) Eat
b) See
c) Walk
d) Speak
Ans: (c) Walk
31. Sand is spread on icy roads to __ friction.
a) Increase
b) Decrease
c) Eliminate
d) None of these
Ans: (a) Increase
32. A matchstick lights up due to __.
a) Gravity
b) Magnetism
c) Friction
d) Electricity
Ans: (c) Friction
33. Friction converts kinetic energy into __ energy.
a) Heat
b) Electrical
c) Potential
d) Light
Ans: (a) Heat
34. Athletes wear special shoes to __ friction.
a) Increase
b) Decrease
c) Remove
d) None of these
Ans: (a) Increase
35. The force that helps a car to stop is __.
a) Gravity
b) Friction
c) Magnetism
d) Air resistance
Ans: (b) Friction
36. Lubricants make a surface __.
a) Rough
b) Sticky
c) Smooth
d) Hard
Ans: (c) Smooth
37. Chalk writing on a blackboard is possible due to __.
a) Gravity
b) Friction
c) Magnetism
d) Air resistance
Ans: (b) Friction
38. Oil and grease __ friction.
a) Increase
b) Reduce
c) Maintain
d) Do not affect
Ans: (b) Reduce
39. Why do swimmers wear tight suits?
a) To increase friction
b) To reduce fluid friction
c) To look stylish
d) To slow down in water
Ans: (b) To reduce fluid friction
40. Air resistance is a type of __ friction.
a) Rolling
b) Sliding
c) Fluid
d) Static
Ans: (c) Fluid
