Questions
23
Complete the sentence. Friction always ____________
Answer: opposes the motion
26
The force of friction acts in a direction _____ to the direction of motion of object.
Answer: Opposite
27
The coefficient of static friction is
Answer: Equal to the tangent of the angle of friction
28
Which of the following kinetic friction is smaller?
Answer: Rolling friction
29
A mass of 4kg rests on a horizontal plane. The plane is gradually inclined until at an angle θ= 15° with the horizontal, the mass just begins to slide. What is the coefficient of static friction between the block and the surface?
Answer: 0.27
31
The ratio of the limiting force of friction (F) to the normal reaction (R) is known as
Answer: Coefficient of friction
33
When the two surfaces in contact have a thick layer of lubricant in between them, it is known as
Answer: Both ‘a’ and ‘b’
34
The force of friction is maximum when the surface
Answer: Is on the point of motion
37
The clutch is placed in four-wheeler, in between
Answer: Engine and gear box
38
In rotation of shaft, the power lost in friction is given by
Answer: W x µ x V Watts
40
Mobil oil is used in scooters and bikes for which purpose?
Answer: None of these
