MS Master of Mechanical Engineering 2 — Questions and Answers
Question 1: What is the Bernoulli equation primarily used for in fluid mechanics?
- Relating pressure, velocity, and elevation along a streamline in inviscid flow (Correct answer)
- Calculating viscous shear stress
- Determining turbulent flow patterns
- Measuring fluid compressibility
Correct answer: Relating pressure, velocity, and elevation along a streamline in inviscid flow
Bernoulli's equation states that along a streamline in steady, inviscid flow, the sum of pressure, kinetic, and potential energy per unit volume remains constant.
Question 2: In CNC machining, what does the G-code command G02 typically instruct the machine to perform?
- Circular interpolation in the clockwise direction (Correct answer)
- Linear interpolation
- Tool change
- Rapid positioning
Correct answer: Circular interpolation in the clockwise direction
G02 commands the CNC machine to move the cutting tool in a clockwise circular arc at the programmed feed rate.
Question 3: What does the term 'stress concentration factor' (Kt) represent in mechanical design?
- The ratio of maximum stress to nominal stress near a geometric discontinuity (Correct answer)
- The factor of safety for a part
- The yield strength ratio
- The elastic modulus ratio
Correct answer: The ratio of maximum stress to nominal stress near a geometric discontinuity
The stress concentration factor Kt is the ratio of the peak local stress at a geometric discontinuity (hole, notch, fillet) to the nominal stress in the net section.
Question 4: What is the difference between conduction and convection heat transfer?
- Conduction occurs in stationary media; convection involves fluid motion (Correct answer)
- Conduction requires fluid; convection does not
- Both are identical processes
- Convection only occurs in solids
Correct answer: Conduction occurs in stationary media; convection involves fluid motion
Conduction transfers heat through a stationary medium via molecular vibration, while convection transfers heat through the bulk motion of a fluid.
Question 5: In a gear system, what does the term 'gear ratio' determine?
- The relationship between input and output speed and torque (Correct answer)
- The number of gear teeth only
- The material strength of gears
- The lubrication requirement
Correct answer: The relationship between input and output speed and torque
The gear ratio determines how speed and torque are transformed between input and output shafts; a higher gear ratio reduces speed and increases torque proportionally.
Question 6: What is the purpose of tolerance stack-up analysis in mechanical assembly design?
- Determining how individual part tolerances accumulate to affect final assembly fit (Correct answer)
- Calculating part weight
- Selecting material grades
- Designing cooling systems
Correct answer: Determining how individual part tolerances accumulate to affect final assembly fit
Tolerance stack-up analysis determines the worst-case or statistical variation in critical assembly dimensions caused by the accumulation of individual part tolerances.
MS Master of Mechanical Engineering 2
What is the Bernoulli equation primarily used for in fluid mechanics?