MCQs on Friction

Friction

Q1. The force of friction acts in a direction _____ to the direction of motion of the object.

a. Same.

b. Opposite👈 

c. Perpendicular.

d. Downwards

Q2. The force of friction depends upon 

a. Nature of surface of contact. 

b. The material of objects in contact. 

c. Both ‘a’ and ‘b’👈 

d. None of the above

Q3. The body will move only when 

a. Force of friction = applied force. 

b. The force of friction < applied force👈 

c. Force of friction > applied force.

d. All of the above 

Q4. The ratio of the limiting force of friction (F) to the normal reaction (R) is known as 

a. Coefficient of friction👈 

b. Force of friction. 

c. The angle of friction. 

d. None of the above

Q5. The coefficient of friction (µ) is equal to? 

a. TanΦ👈 

b. SinΦ. 

c. CotΦ. 

d. CosΦ 

                        (Where Φ = angle of friction)

Q6. The force of friction (F) is equal to 

a. µR/2 

b. µR👈 

c. 2µR 

d. µR/3 

Q7. The value of Normal reaction (R) for the following figure is

a. W – PSinθ👈 

b. W + PSinθ 

c. P – WSinθ 

d. P + WSinθ 

(Where, W = Weight of block, P = Applied force, µ = Coefficient of friction, θ = Angle)

Q8. When the two surfaces in contact have a thick layer of lubricant in between them, it is known as 

a. Solid friction. 

b. Rolling friction. 

c. Greasy friction. 

d. Film friction👈 

Q9. When the two surfaces in contact have a very thin layer of lubricant in between them, it is known as 

a. Solid friction. 

b. Rolling friction. 

c. Greasy friction. 

d. Film friction👈

Q10.  The force of friction is maximum when the surface

a.  Is on the point of motion👈
b.  Is at rest
c.  Is moving
d.  The friction remains same at all points

Q11.  The types of threads used in Screw jacks are

a.  Metric thread
b.  Square👈
c.  ACME
d.  Buttress

Q12. For a single started thread, the lead is equal to
a.  p/2
b.  p👈
c.  2p
d.  p/3

Where p = pitch

Q13.  The slope of the thread with horizontal is known as
a.  helix
b.  lead
c.  pitch
d.  helix angle👈

Q14.  The flat pivot bearing is used to bear

a.  axial thrust👈
b.  radial thrust
c.  both radial and axial thrust
d.  None of the above

Q15.  In plate clutch, the clutch plate is placed

a. Before flywheel
b.  After pressure plate
c.  In between pressure plate and flywheel👈
d.  None of the above

Q16.  The clutch is placed in the four-wheeler, in between
Engine and gearbox👈
Gear box and differential
Propeller shaft and differential
None of the above

Q17.  The radius of the friction circle is independent of
a.  Weight of the shaft👈
b.  Radius of the shaft
c.  Coefficient of friction
d.  All of the above

Q18.  In rotation of shaft, the power lost in friction is given by
a.  W x µ x V Watts👈
b.  W x µ x V Kilo-watts
c.  W x µ / V Watts
d.  W x µ / V Kilo-watts

Where, W=Weight of shaft, µ=Coefficient of friction, V= Velocity of shaft (in m/s)

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