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UPPSC Lec’21 ME: Daily Practices Quiz. 04-Oct-2021

Quiz: Mechanical Engineering
Exam: UPPSC Lecturer
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 6 Minutes

Q1. A hole of diameter (d) is to be punched through a sheet metal of thickness (t). How much force is required to punch the hole if the ultimate shear stress of the sheet metal is (τ)?
(a) dtτ
(b) π/4 d^2 tτ
(c) πτdt
(d) None of these

Q2. Extrusion is the process of
(a) Producing holes by arc
(b) Marking cup shaped articles using the force of explosion
(c) Pushing the heated billet of metal through the orifice
(d) Metal sharping presses

Q3. Adaptive control feature is used
(a) For automation
(b) Only to give better surface finish to the components
(c) Only to reduce power consumed by machine
(d) For inventory control

Q4. In a CNC machine tool, encoder is used to sense and control
(a) Spindle speed
(b) Spindle position
(c) Table position
(d) All of these

Q5. A jig is defined as a device which
(a) Holds and locates a work-piece and guides and controls one or more cutting tools
(b) Holds and locates a work piece during an inspection or for a manufacturing operation (c) Is used to check the accuracy of a work piece
(d) All of the above

Q6. During sintering of a powder metal compact, the following process takes place
(a) Some of the pores grow
(b) Powder Particles do not melt but a bond is formed between them
(c) All the pores reduce in size and bond occurs due to melting
(d) Powder particles fuse and join

Solutions

S1. Ans. (c)
Sol. Punching force, F = Ltτ
Where L is length of periphery
t = thickness
τ = ultimate shear strength
For circular section L = π d
∴ F = πdtτ

S2. Ans. (c)
Sol. Extrusion is the process of confining the metal in a closed cavity and then allowing it to flow through the provided cavity by pushing the either heated or cold billet of metal. The types of extrusion are
Forward extrusion
Backward extrusion
Hydrostatic extrusion
Impact extrusion

S3. Ans. (a)
Sol. Adaptive control feature is used for automation

S4. Ans. (c)
Sol. In a CNC machine tool, encoder is used to sense and control Table position.

S5. Ans. (a)
Sol. A jig is defined as a device which holds and locates a work piece and guides and controls one or more cutting tools. The jigs are used for holding and guiding the tool in drilling, reaming or tapping operations

S6. Ans. (b)
Sol. During sintering of powder metal compact, powder particles do not melt but a bond is formed between them.

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