Quiz:Mechanical Engineering 21 April 2020

Quiz: Mechanical Engineering
Exam: ISRO (TECHNICAL ASST.)
Topic: Miscellaneous

Each question carries 4 mark.
Negative marking: 1 mark
Time: 15 Minute

Q1. In slider crank mechanism, secondary forces fluctuate with
(a) the rotating frequency
(b) double the rotating frequency
(c) four times of the rotating frequency
(d) half the rotating frequency

Q2. Venturimeter works on the basis of
(a) Newton’s law
(b) Pascal’s law
(c) Archimedes’ law
(d) Bernoulli’s principle

Q3. Which of the following statements is/are true for thermodynamics?
1.Work is path independent function
2.Work is path dependent function
3.Heat and work are completely interchangeable
4.Work is the area under the curve in a PV diagram
(a) 1 and 2
(b) 1 and 3
(c) 2 and 4
(d) 2 and 3

Q4. If for a turning job, the length of the work is 200 mm and the taper is 1:50, the set-over required for the tail stock to achieve the taper is
(a) 3 mm
(b) 2 mm
(c) 4 mm
(d) 0.5 mm

Q5. The perimeter of a right-angle triangle is 24 mm. Its hypotenuse is 10 mm. The area (in mm^2) of the triangle is
(a) 25
(b) √24
(c) 24
(d) 36

Q6. Buoyant force for a floating body passes through
(a) CG of the body
(b) Centroid of the displaced volume
(c) Midpoint joining CG and meta-center
(d) None of the above

Q7. H7g6 fit provided on an assembly is
(a) An interference fit
(b) A clearance fit
(c) A transition fit
(d) A nonstandard fit

Q8. If the plot for a Newtonian fluid is drawn between shear stress and shear strain then the shape of the curve is
(a) elliptic
(b) straight line
(c) parabolic
(d) hyperbolic

Q9. The latent heat load in an auditorium is 40% of the sensible heat load. The value of Sensible Heat Factor (SHF) is equal to
(a) 0.25
(b) 0.5
(c) 0.71
(d) 1.0

Q10. Which of the following is true about the amount of heat flow in unit time for conduction?
(a) Decreases with increase in area of the body
(b) Increases with increase in area of the body
(c) Increases with increase in thickness of the body
(d) Decreases with increase in temperature difference between faces of the body

Solutions

S1. Ans.(b)
Sol. In slider crank mechanism, secondary forces fluctuate with double the rotating frequency.
i.e. V=rw[sinθ+(sin2θ)/2n]

S2. Ans.(d)
Sol. Venturimeter works on the Bernoulli’s principle.

S3. Ans.(c)
Sol. Work is a path dependent function and area under curve in a PV diagram represents the work done in a process.

S4. Ans.(c)
Sol. Set-over or offset required on tail stock for taper turning=taper X length of workpiece
Set over or offset length= 1/50 X 200=4 mm

S5. Ans.(c)
Sol. Let, perpendicular and base of the right-angle triangle are a and b.
Then,a+b=14.
a^2+b^2=10^2.
(a+b)^2=14^2.
a^2+b^2+2ab=196.
2ab=96.
ab/2=24 (area of triangle)

S6. Ans.(b)
Sol. Buoyant force for a floating body passes through centroid of the displaced volume.

S7. Ans.(b)
Sol. H7g6 defines the clearance fit.

S8. Ans.(b)
Sol. Shear stress is directly proportional to shear strain for a Newtonian fluid; hence the curve is a straight line.

S9. Ans (c)
Sol. Given LH = 0.4 SH
Now, SHF = SH/(SH+LH)=1/1.4=0.71

S10. Ans.(b)
Sol. According to Fourier law of conduction, heat flow per unit time between two faces of the body is directly proportional to area of the body.
If A↑ then Q↑.

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