Q 1 – Friction is a
(a) non-contact force
(b) contact force
(c) magnetic force
(d) electrostatic force
Ans. (b) contact force
Q 2 – Which of the following produces the least friction?
(a) Sliding friction
(b) Rolling friction
(c) Composite friction
(d) Static friction
Ans. (b) Rolling friction
Q 3 – Friction always
(a) opposes the motion
(b) helps the motion
(c) both (a) and (b)
(d) none of these
Ans. (a) opposes the motion
Q 4 – Friction can be reduced by using
(a) oil
(b) grease
(c) powder
(d) all of these
Ans. (d) all of these
Q 5 – Static friction is less than
(a) sliding friction
(b) rolling friction
(c) both (a) and (b)
(d) none of these
Ans. (d) none of these
Q 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.
Ans. (d) irrespective of whether the objects are solid, liquid or gaseous.
Q 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
Ans. (a) Stone
Q 8 – The shape of an aeroplane is like a
(a) dog
(b) bird
(c) car
(d) all of these
Ans. (b) bird
Q 9 – Friction is
(a) foe
(b) friend
(c) both (a) and (b)
(d) none of these
Ans. (c) both (a) and (b)
Q 10 – Friction due to fluids is called
(a) force
(b) pressure
(c) friction
(d) drag
Ans. (d) drag
Q 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
Ans. (b) Surface of tyres
Q 12 – A toy car released with the same initial speed will travel farthest on
(a) muddy surface
(b) polished marble surface
(c) cemented surface
(d) brick surface
Ans. (b) polished marble surface
Q 13 – If we apply oil on door hinges, the friction will
(a) increase
(b) decrease
(c) disappear altogether
(d) will remain unchanged
Ans. (b) decrease
Q 14 – Lubricant
(a) reduce friction
(b) increase friction
(c) both (a) and (b)
(d) none of these
Ans. (a) reduce friction
Q 15 – Force of friction depends on
(a) roughness of surface
(b) smoothness of surface
(c) inclination of surface
(d) all of these
Ans. (d) all of these
Q 16 – Fluids are
(a) liquids
(b) gases
(c) both (a) and (b)
(d) none of these
Ans. (c) both (a) and (b)
Q 17 – Which is a streamlined object?
(a) Boats
(b) Aeroplanes
(c) Ships
(d) All of these
Ans. (d) All of these
Q 18 – Smooth surface has
(a) less friction
(b) more friction
(c) sometimes less and sometimes more
(d) all of these
Ans. (a) less friction
Q 19 – Which of the following is responsible for wearing out of bicycle tyres?
(a) Muscular force
(b) Magnetic force
(c) Frictional force
(d) Electrostatic force
Ans. (c) Frictional force
Q 20 – It is difficult to walk on an oily floor because
(a) Floor gets spoiled
(b) There is more resistance
(c) Force of friction is high
(d) Force of friction is very less
Ans. (d) Force of friction is very less
Q 21 – Spring balance is a device used for measuring the _____________ acting on an object.
(a) mass
(b) pressure
(c) force
(d) None of the above
Ans. (c) force
Q 22 – A matchstick struck on a matchbox catches fire easily because
(a) Friction may cause fire
(b) Of chemical reaction
(c) Force heated the match stick
(d) None of the above
Ans. (a) Friction may cause fire
Q 23 – Tyres are treaded to
(a) look good
(b) Increase friction
(c) increase its longevity
(d) increase the weight of the tyre
Ans. (b) Increase friction
Q 24 – Lubricants are substances which
(a) Increase friction
(b) Are used to light a fire
(c) Reduce friction
(d) Are used to put out a fire
Ans. (c) Reduce friction
Q 25 – Sliding friction is _________ than / to rolling friction
(a) smaller
(b) greater
(c) equal
(d) None of the above
Ans. (b) greater
Q 26 – The frictional force exerted by fluids is also called ______
(a) drug
(b) drag
(c) drop
(d) drown
Ans. (b) drag
Q 27 – Four children were asked to arrange forces due to rolling, static and sliding frictions in increasing order. Their arrangements are given below. Choose the correct arrangement.
(a) Rolling, Static, Sliding
(b) Static, Rolling, Sliding
(c) Rolling, sliding, static
(d) Sliding, Static, Rolling
Ans. (c) Rolling, sliding, static
Q 28 – A boat or an aeroplane has a pointed or tapering front/head. Why?
(a) To increase the friction of the fluid
(b) To reduce the friction of the fluid
(c) To look good
(d) For no reason
Ans. (b) To reduce the friction of the fluid
Q 29 – The sole of the shoes becomes plain after wearing them for several months. The reason is
(a) Wearing out due to friction
(b) Wearing out due to no friction
(c) Sole is of bad quality
(d) None of the above
Ans. (a) Wearing out due to friction
Q 30 – What is the frictional force exerted by fluids called?
(a) Lift
(b) Drag
(c) Rolling friction
(d) Dynamic friction
Ans. (b) Drag
Q 31 – The substance which reduces friction are called
(a) Lubricants
(b) Wheels
(c) Powder
(d) Graphite
Ans. (a) Lubricants
Q 32 – Friction produces:
(a) Motion
(b) Force
(c) Heat
(d) Light
Ans. (c) Heat
Q 33 – Soapy water on the floor would make it
(a) Cleaner
(b) Difficult to walk
(c) More hygienic
(d) Easier to walk
Ans. (b) Difficult to walk
Q 34 – Thermos flask keeps hot liquid hot and cold liquid cold by
(a) Heating
(b) Friction
(c) Preventing heat loss
(d) Cooling
Ans. (c) Preventing heat loss
Q 35 – Why are certain bodies streamlined?
(a) To increase friction
(b) To decrease weight
(c) To reduce friction
(d) To increase weight
Ans. (c) To reduce friction
Q 36 – What is the value of sliding friction for an object which requires 7 N of force to move it from rest?
(a) 7 N
(b) Greater than 7 N
(c) Less than 7 N
(d) 14 N
Ans. (c) Less than 7 N
Q 37 – Force of friction depends on
(a) Smoothness of surface
(b) Roughness of surface
(c) Inclination of surface
(d) All of the above
Ans. (d) All of the above
Q 38 – What type of a force is friction?
(a) Contact force
(b) Non-contact force
(c) Electrostatic force
(d) Magnetic force
Ans. (a) Contact force
Q 39 – A body will remain in a state of motion on rolling on the ground if
(a) Friction is absent
(b) Friction is acting in the same direction
(c) Friction is very large
(d) All of the above
Ans. (a) Friction is absent
Q 40 – Which of the following statements is correct?
(a) Rolling is easier than sliding.
(b) Sliding is easier than rolling.
(c) Dragging is easier than sliding.
(d) Dragging is easier than rolling.
Ans. (a) Rolling is easier than sliding.