Test: Fluctuating Load Consideration For Design & Miscellaneous - 2 - Mechanical Engineering MCQ

For a disk of moment of inertia I the spin and precession angular velocities are ω and ω_p respectively. The magnitude of gyroscopic couple is………… 

A cylindrical shaft is subjected to an alternating stress of 100 MPa. Fatigue strength to sustain 1000 cycles is 490 MPa. If the corrected endurance strength is 70 MPa, estimated shaft life will be  

In designing a shaft for variable loads, the S.N. diagram can be drawn by 

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

Fatigue strength of a rod subjected to cyclic axial force is less than that of a rotating beam of the same dimensions subjected to steady lateral force. What is the reason?   

The design calculations for members subject to fluctuating loads with the same factor of safety yield the most conservative estimates when using 

Assertion (A): There is a danger of locomotive wheels being lifted above rails at certain speeds.

Reason (R): Lifting of the locomotive wheel above rails at certain speed is due to gyroscopic action. 

A flywheel has a mass of 300 kg and a radius of gyration of 1m. It is given a spin of 100 r.p.m about its horizontal axis. The whole assembly rotates about a vertical axis at 6 rad/sec. The gyroscopic couple experienced will be  

In a semi-infinite flat plate shown in the figure, the theoretical stress concentration factor k_t for an elliptical hole of major axis 2a and minor axis 2b is given by 

Match List I (Mechanical Property) with List II (Measured in Terms of) and select the correct answer using the codes given below the lists:    

A band brake consists of a lever attached to one end of the band. The other end of the band is fixed to the ground. The wheel has a radius of 200 mm and the wrap angle of the band is 270^o. The braking force applied to the lever is limited to 100 N, and the coefficient of friction between the band and the wheel is 0.5. No other information is given.

Que: The maximum tension that can be generated in the band during braking is 

A band brake consists of a lever attached to one end of the band. The other end of the band is fixed to the ground. The wheel has a radius of 200 mm and the wrap angle of the band is 270^o. The braking force applied to the lever is limited to 100 N, and the coefficient of friction between the band and the wheel is 0.5. No other information is given.

Que: The maximum wheel torque that can be completely braked is

A block-brake shown below has a face width of 300 mm and a mean coefficient of friction of 0.25. For an activating force of 400 N, the braking torque in Nm is  

A device for lifting or lowering objects suspended from a hook at the end of a retractable chain or cable is called   

 Consider the following statements regarding the differential of an automobile:

1. The speed of the crown wheel will always be the mean of the speeds of the two road wheels.

2. The road wheel speeds are independent of the number of teeth on the planets.

3. The difference between the speeds of the road wheels depends on the number of teeth on the planets.

4. The ratio of speeds of the road wheels depends upon the number of teeth on the gear wheels attached to them and on the crown wheel.

Of these statements 

In an automobile service station, an automobile is in a lifted up position by means of a hydraulic jack. A person working in the service station gave a tap to one rear wheel and made it rotate by one revolution. The rotation of another rear wheel is 

Rope brake dynamometer uses