Test: Design of Friction Drives - 1 - Mechanical Engineering MCQ

The percentage improvement in power capacity of a flat belt drive, when the wrap angle at the driving pulley is increased from 150° to 210° by an idler arrangement for a friction coefficient of 0.3, is

In a 6 × 20 wire rope, No.6 indicates the  

Self locking in power screw is better achieved by decreasing the helix angle and increasing the coefficient of friction.  

Which of the following stresses are associated with the design of pins in bushed pin-type flexible coupling?    1. Bearing stress        

2. Bending stress        

3. Axial tensile stress        

4. Transverse shear stress

Select the correct answer using the codes given below  

The bolts in a rigid flanged coupling connecting two shafts transmitting power are subjected to 

Two co-axial rotors having moments of inertia I₁, I₂ and angular speeds ω₁ and ω₂ respectively are engaged together. The loss of energy during engagement is equal to 

Which of the following statements regarding laws governing the friction between dry surfaces are correct?    1. The friction force is dependent on the velocity of sliding.

2. The friction force is directly proportional to the normal force.

3. The friction force is dependent on the materials of the contact surfaces.

4. The frictional force is independent of the area of contact 

When the intensity of pressure is uniform in a flat pivot bearing of radius r, the friction force is assumed to act at    

In case of a multiple disc clutch, if n₁ is the number of discs on the driving shaft and n₂ is the number of discs on the driven shaft, then what is the number of pairs of contact surfaces? 

On the motors with low starting torque, the type of the clutch to be used is 

Match List-I with List-II and select the correct answer using the codes given below the lists:  

Code: A B C D

Assertion (A): In design of arms of a pulley, in belt drive, the cross-section of the arm is, elliptical with minor axis placed along the plane of rotation.

Reason (R): Arms of a pulley in belt drive are subjected to complete reversal of stresses and is designed for bending in the plane of rotation. 

Which one of the following belts should not be used above 40°C?  

Assertion (A): Crowning is provided on the surface of a flat pulley to prevent slipping of the belt sideways.

Reason (R): Bell creep, which is the reason for slip of the belt sideways, is fully compensated by providing crowning on the pulley. 

Which one of the following statements relating to belt drives is correct?  

In a Belt drive, if the pulley diameter is doubled keeping the tension and belt width constant, then it will be necessary to   

Centrifugal tension in belts is