MES Jr. Grade • Paper-II
The tensile force required to cause an elongation 0.045 mm in a steel rod of 1000 mm length and 12 mm diameter, is (where E= 2×106 kg/cm2)
A)
166 kg
B)
102 kg
C)
204 kg
D)
74 kg
Use the axial deformation relation: \(\delta = \frac{PL}{AE}\), so \(P = \frac{\delta AE}{L}\).
Given:
- \(\delta = 0.045\,\text{mm} = 0.0045\,\text{cm}\)
- \(L = 1000\,\text{mm} = 100\,\text{cm}\)
- \(d = 12\,\text{mm} = 1.2\,\text{cm}\)
- \(A = \frac{\pi d^2}{4} = \frac{\pi(1.2)^2}{4} \approx 1.131\,\text{cm}^2\)
- \(E = 2\times 10^6\,\text{kg/cm}^2\)
Now,
\[
P = \frac{0.0045 \times 1.131 \times 2\times 10^6}{100}
\approx 102\,\text{kg}
\]
So the correct option is **b) 102 kg**.
Why the others are incorrect:
- **a) 166 kg**: too high; would correspond to a larger elongation or smaller length.
- **c) 204 kg**: about double the correct value, likely from a calculation error in area or unit conversion.
- **d) 74 kg**: too low; would result from underestimating the area or modulus.
Hence, the required tensile force is **102 kg**.
MES Jr. Grade • Paper-II
Coaxing is the procedure of increasing
A)
metal strength by cycling
B)
fatigue limit by overstressing the metal by successively increasing loadings
C)
metal resistance to corrosion by coating
D)
metal hardness by surface treatment
Coaxing is the process of increasing the fatigue limit of a metal by subjecting it to repeated loading with successively increasing stress levels, so the material becomes less sensitive to fatigue failure. Hence option (b) is correct.
Option (a) is incorrect because cycling alone refers to repeated loading, but coaxing specifically means increasing the fatigue limit by progressively higher loads. Option (c) is incorrect because coating improves corrosion resistance, not coaxing. Option (d) is incorrect because surface treatment may increase hardness, but that is unrelated to coaxing.
MES Jr. Grade • Paper-II
Which of the following is a vector quantity
A)
energy
B)
mass
C)
momentum
D)
speed
Momentum is a vector quantity because it has both magnitude and direction, and its direction is the same as the velocity of the body. Energy, mass, and speed are scalar quantities: they have magnitude only and no direction.
MES Jr. Grade • Paper-II
When trying to turn a key into a lock, following is applied
A)
coplanar force
B)
lever
C)
moment
D)
couple
Turning a key in a lock is an example of a couple: two equal and opposite forces act at different points, producing pure rotation without translation. A key is turned by applying force through the key head, creating a turning effect about the lock axis. "Moment" is a general term for turning effect, but the specific mechanical action here is a couple. "Lever" is a simple machine, not the force system applied. "Coplanar force" only describes forces lying in the same plane and does not specifically represent the turning action.
MES Jr. Grade • Paper-II
Failure of a material is called fatigue when it fails
A)
At the elastic limit
B)
Below the elastic limit
C)
At the yield point
D)
Below the yield point
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Below the elastic limit' (Option B).
MES Jr. Grade • Paper-II
In the case of a flywheel, the maximum fluctuation of energy is the
A)
Sum of maximum and minimum energies
B)
Difference between the maximum and minimum energies
C)
Ratio of the maximum and minimum energy
D)
Ratio of the minimum and maximum energy
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'Ratio of the minimum and maximum energy' (Option D).
MES Jr. Grade • Paper-II
A material subjected to pure shear can fail by
A)
Rankine’s theory only
B)
St. Venant’s theory only
C)
Tresca’s theory only
D)
Any of the above theory
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Tresca’s theory only' (Option C).
MES Jr. Grade • Paper-II
The maximum power is transmitted by a belt when the initial tension is
A)
Half the centrifugal tension
B)
One third the centrifugal tension
C)
Twice the centrifugal tension
D)
Three times the centrifugal tension
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'Twice the centrifugal tension' (Option C).
MES Jr. Grade • Paper-II
Limit of proportionality depends upon
A)
area of cross- section
B)
type of loading
C)
type of material
D)
all of the above
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'all of the above' (Option D).
MES Jr. Grade • Paper-II
The centroid of a cross-section is at
A)
geometric centre
B)
point about which the moment of inertia is zero
C)
point about which the moment of area is zero
D)
neutral axis always
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'point about which the moment of inertia is zero' (Option B).
MES Jr. Grade • Paper-II
For minimizing speed fluctuations of an engine as a prime mover, it must have
A)
Only flywheel fitted to the crankshaft
B)
A governor fitted in the system
C)
Both a flywheel and a governor provided in the system
D)
Neither a flywheel nor a governor
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'A governor fitted in the system' (Option B).
MES Jr. Grade • Paper-II
A higher pair can be replaced by a
A)
Two revolute pair and two additional linkages
B)
Two revolute pair and one additional linkages
C)
One revolute pair and one additional linkages
D)
None of these
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'One revolute pair and one additional linkages' (Option C).
MES Jr. Grade • Paper-II
The working surface above the pitch surface of the gear tooth is termed as
A)
Addendum
B)
Dedendum
C)
Flank
D)
Face
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'Flank' (Option C).
MES Jr. Grade • Paper-II
An orthotropic material has
A)
non- homogeneous properties
B)
inelastic properties
C)
different properties in three perpendicular directions
D)
same properties in orthogonal directions
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'same properties in orthogonal directions' (Option D).
MES Jr. Grade • Paper-II
Railway carriage coupling have
A)
Square thread
B)
Acme thread
C)
Knuckle thread
D)
Buttress thread
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'Knuckle thread' (Option C).
MES Jr. Grade • Paper-II
In a kinematic chain, a quaternary joint is equivalent to
A)
One binary joint
B)
Two binary joint
C)
Three binary joint
D)
Four binary joint
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'Two binary joint' (Option B).
MES Jr. Grade • Paper-II
Effect of friction, at the sleeve of a centrifugal governor is to make it
A)
More sensitive
B)
More stable
C)
Insensitive over a small range of speed
D)
Unstable
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'More stable' (Option B).
MES Jr. Grade • Paper-II
Match list-I with list –II and select the correct answer using the codes given below the lists:
List-I: A. Ratio of lateral strain to linear strain, B. Ratio of stress to strain, C. Ratio of extension to original length, D. Ratio of axial pull to area of section
List-II: 1. Strain, 2. Poisson’s ratio, 3. Tensile stress, 4. young’s modulus
A)
4 2 3 1
B)
4 2 1 3
C)
2 4 3 1
D)
2 4 1 3
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is '4 2 3 1' (Option A).
MES Jr. Grade • Paper-II
Match list-I (application) with list-II (drive element) and select the correct answer using the codes given below the lists:
List-I: A. Automobile differential, B. Bicycle, C. Planning machine, D. Radiator fan of automobile
List-II: 1. Flat belt, 2. V- belt, 3. Chain drive, 4. Gear drive
A)
4 3 1 2
B)
1 3 4 2
C)
4 2 1 3
D)
1 2 4 3
Based on established principles in the relevant subject area, the correct and most appropriate choice is '4 3 1 2' (Option A).
MES Jr. Grade • Paper-II
Stress concentration in a machine component of ductile material is not so harmful as it is in brittle material because
A)
In ductile material local yielding may distribute stress concentration
B)
Ductile material has larger Young’s Modulus
C)
Poison’s ratio is larger in ductile materials
D)
Modulus of rigidity is larger in ductile materials
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Poison’s ratio is larger in ductile materials' (Option C).
MES Jr. Grade • Paper-II
Which of the following plane mechanism represents the structure
A)
Three-bar mechanism
B)
Four-bar mechanism
C)
Five-bar mechanism
D)
Six-bar mechanism
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'Six-bar mechanism' (Option D).
MES Jr. Grade • Paper-II
A rigid plastic material has the following stress- strain relation:
A)
Stress is proportional to strain up to a point and then it is constant.
B)
Strain is zero up to a stress level and then stress remains constant.
C)
Strain is zero for all stresses.
D)
Strain is zero up to a point and then it is constant for any increase in stress.
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Strain is zero up to a point and then it is constant for any increase in stress.' (Option D).
MES Jr. Grade • Paper-II
The most common type of cam follower used in aircraft engines is
A)
Spherical
B)
Knife edge
C)
Roller
D)
Mushroom
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'Spherical' (Option A).
MES Jr. Grade • Paper-II
Match list-I (application) with list-II (drive element) and select the correct answer using the codes given below the lists:
List-I: A. Sliding pair, B. Revolute pair, C. Rolling pair, D. Spherical pair
List-II: 1. A road roller rolling over the ground, 2. Crank shaft in a journal bearing in an engine, 3. Ball and socket joint, 4. Piston and cylinder, 5. Nut and screw
A)
5 2 4 3
B)
4 3 1 2
C)
5 3 4 2
D)
4 2 1 3
Based on established principles in the relevant subject area, the correct and most appropriate choice is '5 3 4 2' (Option C).
MES Jr. Grade • Paper-II
In a slider-crank mechanism, the velocity of piston becomes maximum when
A)
Crank and connecting rod are in line with each other
B)
Crank is perpendicular to the line of stroke of the piston
C)
Crank and connecting rod are perpendicular
D)
Crank is 1200 with the line of stroke
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'Crank and connecting rod are in line with each other' (Option A).
