Mechanical Engineering (Test 5)

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Mechanical Engineering

Mechanical Engineering
| Engineering Mathematics | | Applied Mechanics and Design | | Fluid Mechanics and Thermal Sciences | | Materials, Manufacturing and Industrial Engineering |
Q.1
Match the casting defects (Group A) with the probable causes (Group B): 
Group A                                         Group B
(p) Hot tears                                  1: Improper fusion of two streams of liquid metal 
(q) Shrinkage                                 2: Low permeability of the sand mould 
(r) Blow holes                                3: Volumetric contraction both in liquid and solid stage 
(s) Cold Shut                                 4: Differential cooling rate
A. P-1, Q-3, R-2, S-4
B. P-4, Q-3, R-2, S-1
C. P-3, Q-4, R-2, S-1
D. P-1, Q-2, R-4, S-3
Answer : Option B
Explaination / Solution:
No Explaination.


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Q.2
The coefficient of restitution of a perfectly plastic impact is
A. 0
B. 1
C. 2
D.
Answer : Option A
Explaination / Solution:

Coefficient of Re stitution = Relative velocity of separation/Relative velocity of approach
                                         = O for perfectly plastic impact
 since both bodies clinge together after impact.

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Q.3
The “Jominy test” is used to find
A. Young’s modulus
B. hardenability
C. yield strength
D. thermal conductivity
Answer : Option B
Explaination / Solution:

Jominy Test measures the hardenability of the steels.

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Q.4
Which one of the following is the most conservative fatigue failure criterion?
A. Soderberg
B. Modified Goodman
C. ASME Elliptic
D. Gerber
Answer : Option A
Explaination / Solution:
No Explaination.


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Q.5
In abrasive jet machining, as the distance between the nozzle tip and the work surface increases, the material removal rate
A. Increases continuously
B. Decreases continuously
C. Decreases, becomes stable and then increases
D. Increases, becomes stable and then decreases
Answer : Option D
Explaination / Solution:


Graph of abrasive flow rate v/s tool tip distance metal removal rate is proportional to abrasive flow rate. As the tool tip distance increase, area of contact increases which results in higher metal removal rate. But after a certain distance, the jet looses its velocity, hence metal removal rate decreases.

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Q.6
Cylindrical pins of  mm diameter are electroplated in a shop. Thickness of the plating is 30+2.0 micron. Neglecting gage tolerances, the size of the GO gage in mm to inspect the plated components is
A. 25.042
B. 25.052
C. 25.074
D. 25.084
Answer : Option B
Explaination / Solution:


Go gauge = max. Limit = 25.052  

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Q.7
Match the following: 
NC Code                  Definition 
P. M05                     1. Absolute coordinate system 
Q. G01                     2. Dwell 
R. G04                     3. Spindle stop 
S. G90                     4. Linear interpolation
A. P-2, Q-3, R-4, S-1
B. P-3, Q-4, R-1, S-2
C. P-3, Q-4, R-2, S-1
D. P-4, Q-3, R-2, S-1
Answer : Option C
Explaination / Solution:
No Explaination.


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Q.8
Annual demand for window frames is 10000. Each frame costs Rs. 200 and ordering cost is Rs. 300 per order. Inventory holding cost is Rs. 40 per frame per year. The supplier is willing to offer 2% discount if the order quantity is 1000 or more, and 4% if order quantity is 2000 or more. If the total cost is to be minimized, the retailer should
A. order 200 frames every time
B. accept 2% discount
C. accept 4% discount
D. order Economic Order Quantity
Answer : Option C
Explaination / Solution:
No Explaination.


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Q.9
Consider a single degree-of-freedom system with viscous damping excited by a harmonic force. At resonance, the phase angle (in degree) of the displacement with respect to the exciting force is
A. 0
B. 45
C. 90
D. 135
Answer : Option C
Explaination / Solution:
No Explaination.


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Q.10
In a condenser of a power plant, the steam condenses at a temperature of 60o C . The cooling water enters at 30o C and leaves at 45o C . The logarithmic mean temperature difference (LMTD) of the condenser is 
A. 16.2o C 
B. 21.6o C
C. 30o C 
D. 37.5o C
Answer : Option B
Explaination / Solution:

Flow configuration in condenser as shown below. 


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