The ultimate guide to mechanical engineering viva questions

Here are some machine design viva questions to make your profession in mechanical engineering and these mechanical engineering questions will be very much required for you to groom yourself.

1. Segment or Circular disc with uniform thickness is the form used to make sunk key and it is known as:

a) Woodruff key

b) Feather key

c) Kennedy key

d) Saddle key

Answer: a) Woodruff Key

2. In the assembly of pulley, key and shaft:

a) Key is made the strongest

b) All the three are designed for equal strength

c) Key is made the weakest

d) Pulley is made the weakest

Answer: c) Key is made the weakest so that it is cheap and easy to replace in case of failure

3. In a steam engine, piston rod and the crosshead are usually connected by means of:

a) Ball Joint

b) Cotter Joint

c) Universal Joint

d) Knuckle Joint

Answer: b) Cotter Joint

Reason: valve rod and it stem and piston connecting rods are the example

4) The distribution of force along the length of the key in a parallel sunk key is:

a) varies exponentially, being more at the torque input end

b) varies exponentially, being less at torque output end

c) Varies linearly

d) is uniform throughout

Answer: c) varies exponentially, being more at the torque input end, The parallel sunk keys may be of rectangle-shaped or rectangle area consistent wide and size throughout. It may be mentioned that a parallel key is a blend less and is used where the lever, equipment or other propagation part needs to slip along the base. In developing a key, causes due to fit of the key are ignored and it is believed that the submission of causes along the duration of key is consistent.

5) The key of a rectangular section and with the help of shaft it is connencted to a spur gear transmitting power. Stresses developed in the key is fare:

a) Both shear and bearing stresses

b) Bearing stress alone

c) Shear stress alone

d) Shearing, Bearing and Bending stresses

Answer: a) Both shear and bearing stresses

6) The rods joined by the cotter doesnot allow any relative motion and that is when cotter joint is used and it is capable of transmitting

a) An axial tensile as well as compressive load

b) Twisting Moment

c) Only compressive axial load

d) The bending moment

Answer: a) An axial tensile as well as compressive load

Reason: A cotter is a set pitching wedge formed piece of metal. This is used to plug strictly two supports which transfer movement in the axial route, without spinning. These joint parts may experience tensile or compression causes along the axes of the rods

7) The gib and cotter joint are subjected too:

a) Single shear and crushing

b) Double shear and crushing

c) Single Shear only

d) Double Shear only

Answer: d) Double shear and crushing as a cotter joint is a short-term attachmentand is used to link strictly two co-axial supports or bars which are exposed to axial tensile or compression forces.

8) Flange connecting a key and coupling to a shaft is likely to fail in:

a) Bending

b) Torsion

c) Tension

d) Shear

Answer: d) Shear is the main stress on the key

9) A square key of side d/4 is to be fitted on a shaft of diameter d and in the hub of a pulley. If the material of the key and shaft is same and the two are to be equally strong in shear, what is the length of the key?

a) 4π d / 5

b) 3π d / 4

c) 2π d / 3

d) π d / 2

Answer: d) π d / 2

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