Let's Prepare for Technical Interview (Part-6)

Mechanical engineering interview questions:

Que: What is bending moment?
Ans: When a moment is applied to bend an element, a bending moment exists in the element.

Que: What are the points in the Stress Strain curve for Steel?
Ans: Proportional limit, elastic limit or yield point, ultimate stress and stress at failure.

Que: Define Reynolds number?
Ans: Reynolds number is the ratio of inertial force and viscous force. It is a dimensionless number. It determines the type of fluid flow.

Que: What is a Newtonian fluid?
Ans: A Newtonian fluid possesses a linear stress strain relationship curve and it passes through the origin. The fluid properties of a Newtonian fluid do not change when any force acts upon it.

Que: How many Joules is 1 BTU?
Ans: 1 BTU is equal to 1055.056 joules.

Que: What is PS?
Ans: PS is Pferdestarke, the German unit for Horsepower.

Que: Explain Otto cycle?
Ans: Otto cycle can be explained by a pressure volume relationship diagram. It shows the functioning cycle of a four stroke engine. The cycle starts with an intake stroke, closing the intake and moving to the compression stroke, starting of combustion, power stroke, heat exchange stroke where heat is rejected and the exhaust stroke. It was designed by Nicolas Otto, a German engineer.

Que: Explain the nomenclature of a 6203-ZZ bearing?
Ans: 6 is the type code, which shows it is a single-row ball bearing, 2 is the series, means light, 03 is the bore, which is 17 mm and ZZ is the suffix meaning double shielded bearing.

Que: What is Gear ratio?
Ans: It is the ratio of the number of revolutions of the pinion gear to one revolution of the idler gear.

Que: What is Annealing?
Ans: It is a process of heating a material above the re-crystallization temperature and cooling after a specific time interval. This increases the hardness and strength if the material.