FREE Master of Engineering Machine Design Questions and Answers

Question 1

Which of the following, when applied to power screws, is the right formula to calculate torque when the load is reduced during machine design? (W=weight in N, =angle of inclination, =angle of friction)

Accepted Answer

W tan (θ – ϕ)

Answer

In machine design, when a power screw is used to lower a load, the torque required to overcome friction and the load itself is calculated using the formula W tan (θ – ϕ). Here, W is the load, θ is the helix angle of the screw, and ϕ is the friction angle, representing the resistance encountered during the lowering motion.

Question 2

Which of the following represents a screw in dominance?

Accepted Answer

Large load carrying capacity

Answer

Power screws are mechanical devices specifically designed to convert rotational motion into linear motion, and their primary advantage, or 'dominance,' lies in their ability to handle and sustain very large axial loads. This characteristic makes them ideal for applications requiring significant force transmission, such as jacks and presses.

Question 3

According to ASME code, what is the maximum shear stress for a material with keyway effect and ultimate tensile strength (Sut)?

Accepted Answer

0.135 Sut

Answer

According to the ASME code for shaft design, the maximum permissible shear stress for a material with a keyway effect is reduced to account for the stress concentration caused by the keyway. This reduction is typically specified as 0.135 times the ultimate tensile strength (Sut) of the material, reflecting the weakening effect of the keyway on the shaft's strength.

Question 4

Which of the following components only experiences the bending moment when transferring torque?

Accepted Answer

Axle

Answer

An axle is a shaft that supports a transverse load (like the weight of a vehicle or machine component) while also transmitting torque. The transverse load inherently creates bending moments along the axle's length. Therefore, an axle experiences both bending moment due to the supported load and torsional stress from the transmitted torque, making bending a primary stress when transferring torque.

Question 5

Which one of the following connects two rotating shafts?

Accepted Answer

Coupling

Answer

A coupling is a mechanical device specifically designed to connect two rotating shafts, allowing for the transmission of power and torque between them. Couplings can be rigid or flexible, depending on the need to accommodate misalignment between the shafts. Other options like belt drives and gears transmit power between shafts but do so indirectly, while a key is used to secure components *to* a shaft, not connect two shafts directly.

ME or MEng Master of Engineering Practice Test

ME or MEng Master of Engineering Practice Test

FREE Master of Engineering Machine Design Questions and Answers