UPPSC Lec'21 ME: Daily Practices Quiz. 16-Oct-2021

Quiz: Mechanical Engineering
Exam: UPPSC Lecturer
Topic: Miscellaneous

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

Q1. Percentage of work save in case of single acting pump and double acting pump when we use air vessel in reciprocating pump is respectively
(a) 84.8 % and 39.2%
(B) 39.2 % and 84.8%
(c) 39.2% in both
(d) 84.8 % in both

Q2. Air is flowing over a flat plate with a free steam velocity of 24 m/s, and its kinematic viscosity is 72×10^(-6) If a particular point, the Reynolds number is 30000, its location from the leading edge is.
(a) 0.05 m
(b) 0.07 m
(c) 0.08 m
(d) 0.09 m

Q3. A cup of 10 cm height and 5 cm diameter is to be made from a sheet metal of 2 mm thickness. The number of deductions necessary will be
(a) one
(b) two
(c) three
(d) four

Q4. The bending force required for U-bending, V – bending and Edge – bending will be in the ratio of
(a) 1: 2: 0.5
(b) 2: 1: 0.5
(c) 1: 2: 1
(d) 1: 1: 1

Q5. In single server queuing model if arrival rate is λ and service rate is μ, then what is the probability of the system being utilize?
(a) λ/μ
(b) μ/λ
(c) 1 – λ/μ
(d) ((1-λ)/μ)

Q6. In the Kendall’s notation for representing queuing models the 2nd position represents
(a) Probability law for the arrival
(b) Probability law for the service
(c) Number of channels
(d) Capacity of the system

Solutions

S1. Ans. (a)
Sol. By use of air vessel in reciprocating pump, head loss due to friction in suction as well as in delivery pipe is reduced and by this reduction in head a considerable amount of work is saved.
And percentage of work save in case of single acting pump is 84.8 % and 39.2 % in double acting pump when we use air vessel in reciprocating pump.

S2. Ans.(d)
Sol.
Re=ux/ϑ
x=(30000×72×10^(-6))/24=0.09 m=9 cm

S3. Ans.(c)
Sol. D=√(d^2+4dh)=√(5^2+4×5×10)=15
Limiting draw ratio=D/d=15/5=3
The number of deductions necessary will be three.

S4. Ans. (b)
Sol. The bending force required for U-bending, V – bending and Edge – bending will be in the order of
U – bending > V – bending > Edge – bending

S5. Ans.(a)
Sol. if arrival rate is λ and service rate is μ
Then, Probability of utilization or channel efficiency =λ/μ
∴ Probability of idleness = 1 –λ/μ

S6. Ans.(b)
Sol. Kendall’s Lee notation
▭(a/b/c∶d/e/f)
a: Probability distribution of arrival.
b: Probability distribution of service.
c: Number of servers.
d: Service discipline (FCFS, FCLS).
e: System size.
f: Calling source population.