DMRC (Delhi Metro) Exam Papers - Mechanical
DMRC (Delhi Metro) Exam Papers - Mechanical
1. In nodular iron, graphite is in the form of
a) Cementite
b) Free carbon
c) Flakes
d) Spheroids
2. Hardness of steel depends on
a) Amount of carbon it contains
b) The shape and distribution of the carbides in iron
c) Method of fabrication
d) Contents of alloying elements
3. Too high welding current in arc welding would result in
a) Excessive spatter, under cutting along edges, irregular
deposits, wasted electrodes
b) Excessive piling up of weld metal, poor penetration, wasted electrodes
c) Too small bead, weak weld and wasted electrodes
d) Excessive piling up of weld metal, overlapping without penetration of edges,
wasted electrodes
4. Which of the following has maximum hardness
a) Austenite
b) Pearlite
c) Troostite
d) Martensite
5. The main advantage of line organization is its
a) Effective command and control
b) Defined responsibilities at all levels
c) Rigid discipline in the organization
d) All of the above
6. The mathematical technique for finding the best use of limited resources in an optimum manner is known as
a) Operation research
b) Linear programming
c) Network analysis
d) Queuing theory
7. Which of the following errors are generally distributed in accordance with the Gaussian distribution
a) Controllable errors
b) Calibration errors
c) Avoidable errors
d) Random errors
8. If the radius of wire stretched bya load doubled, then its Young’s modulus will
a) Be doubled
b) Be halved
c) Become four times
d) None of the above
9. Long itudirial stress in a thin cylinder subjected to internal pressure is
a) Half of the hoop stress
b) Twice the hoop stress
c) Equal to the hoop stress
d) One-fourth the hoop stress
10. Hydraulic testing of boilers is done at pressures
a) Below and above atmosphere
b) Slightly above atmospheric pressure
c) At half the working pressure of boiler
d) At 1.5 to 2 times the working pressure
11. Gantry girders are invariably designed to resist
a) Transverse loads only
b) Lateral loads only
c) Transverse and lateral loads
d) Transverse, lateral and axial load
12. If the rotating mass of a rim type flywheel is distributed on another rim type flywheel whose mean radius is half the mean radius of the former, then energy stored in the later at the same speed will be
a) Four times the first one
b) Same as the first one
c) One fourth of the first one
d) One and a half times the first one
13. If a number of forces act on a rigid body, each force may be replaced by an equal and parallel force acting through a fixed point, together with a couple. For the rigid body to be in equilibrium
a) Both resultant force and couple must be zero
b) The resultant couple on the body must be zero
c) The resultant force at the fixed point must be zero
d) None of the above need be zero
14. Whirling speed of a shaft coincides with the natural frequency of its
a) Longitudinal vibration
b) Transverse vibration
c) Torsional vibration
d) Coupled bending torsional vibration
15. A fixed gear having 200 teeth is in mesh with another gear having 50 teeth. The two gears are connected by an arm. The number of turns made by the smaller gear for one revolution of arm about the center of the bigger gear is
a) 4
b) 3
c) 2
d) 5
16. Pick up the wrong statement. A flywheel
a) Is used to limit the inevitable fluctuation of speed
during each cycle
b) Controls the mean speed of rotation
c) Stores up energy and gives up whenever required
d) Regulates the speed during one cycle of a prime mover
17. Purpose of using differential gear in automobile is to
a) Help in turning
b) Control speed
c) Avoid jerks
d) Obtain rear movement
18. The acceleration of Simple Harmonic Motion of a pendulum is proportional to
a) Length of pendulum
b) Time period
c) Angular velocity
d) Displacement
19. A person walks up a stalled escalator in 90 seconds. When standing on the same escalator, now moving, he is carried up in 60 seconds. How much time would it take him to walk up the moving escalator?
a) 30 sec
b) 36 sec
c) 45 sec
d) 54 sec
20. A stone of mass m at the end of a string of length I is whirled in a vertical circle at a constant speed. The tension in the string will be maximum when the stone is
a) At the top of the circle
b) Half-way down from the top
c) Quarter-was down from the top
d) At the bottom of the circle
21. Between section 1 and 2 of a pipe a pump, a heater, a very rough pipe and an orifice plate are placed. The Bernoulli equation can be applied between I and 2 if
a) Orifice plate and heater are removed
b) Heater pump and heater are removed
c) Heater and pump are removed
d) Heater, rough pipe and orifice plates are removed
22. A one dimensional flow is one which
a) Is uniform flow
b) Is steady uniform flow
c) Takes place in straight lines
d) Involves zero transverse component of flow
23. The horizontal component of force on a curved surface is equal to the
a) Product of pressure at its centroid and area
b) Weight of liquid retained by the curved area
c) Force on a vertical projection of the curved surface
d) Weight of liquid vertically above the curved surface