01 ) During metal cutting, low feed and high cutting speed is considered to obtain
Ans :- Surface finish.
Solution :- The surface finish in machining operation depends on
1. Type of chip formation
2. Tool profile and geometry
3. Cutting speed
Surface roughness decreases with the increase
of nose radius.
Hence the surface roughness depends
on cutting speed, feed and depth of cut.
02 ) The ability of a material to withstand varying loads is called
Ans:- fatigue strength.
Solution :-
Fatigue strength:
• It is the highest stress that a material can withstand for a given number of cycles or varying loads without breaking.
Impact strength:
• Impact strength is the capability of the material to withstand a suddenly applied load and is expressed in terms of energy.
Creep strength:
• The maximum stress that a material can withstand for the specified length of time without excessive deformation.
Tensile Strength:
The tensile strength of a material is the maximum amount of tensile stress that it can take before failure.
03 ) Which of the following is CORRECT regarding
the principal planes?
Ans :- At principal plane shear stress is zero.
Solution :-
04 ) The rotational tendency of a force is called
Ans :- Moment.
Solution :- • It is the measure of the tendency of a force to cause a body to rotate about a specific
point or axis.
• For the left end, the clockwise moment is taken as the positive and anticlockwise moment is taken as negative.
• For the right end, the anticlockwise moment
is taken as the positive and clockwise moment is taken as negative.
05 ) The function of Faceplate in a centre-lathe is
Ans :- to hold workpieces which cannot be easily held by any of the other methods.
Solution :- The faceplate is used for holding jobs such as thin and irregularly shaped workpieces
that can not be held between the centres and chucks.
06 ) It is required to produce large amount of steam at low pressure. Which boiler should be used?
Ans :- Lancashire boiler.
Solution :-
The maximum working pressure in a Lancashire boiler is 16 bar.
• It is used where working pressure and power required are moderate.
• Its steam production rate is 9000 kg/hr. Its efficiency is from 50% to 70% depending upon the type of fuel used.
07 ) In a throttling process, which of the following parameters remains constant?
Ans :- Enthalpy.
Solution :- This is a highly irreversible process and is used to reduce the pressure and temperature of the refrigerant in a refrigeration system.
08 ) The hoop stress in a thin cylinder shell is
Ans :- circumferential tensile stress.
Important Points:-
For spherical shell, longitudinal stress and circumferential stress both are equal.
09 ) The shear force is usually associated with:
Ans :- Bending moment.
solution :- The rate of change of bending moment at any section is equal to shear force at that
section.
10 ) NPSH stands for
Ans :- Net positive suction head.
Solution :- NPSH (Net Positive Suction Head) is a measure of the pressure experienced by a fluid on the suction side of a centrifugal pump. It is used to avoid running a pump under conditions which favour cavitation.
