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Engineering Mechanics MCQ Solved Paper for NDA

Thursday 9th of March 2023

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Downlaod Engineering Mechanics MCQ PDF
1. The angle of inclination of the plane at which the body begins to move down the plane, is called
A. Angle of friction
B. Angle of repose
C. Angle of projection
D. None of these
Answer : A
2. Which of the following is the example of lever of first order?
A. Arm of man
B. Pair of scissors
C. Pair of clinical tongs
D. All of the above
Answer : D
3. The maximum efficiency of a lifting machine is
A. 1/m
B. V.R./m
C. m/V.R.
D. 1/(m × V.R.)
Answer : D
4. The forces which meet at one point, but their lines of action __________ on the same plane, are Known as non-coplanar concurrent forces.
A. Lie
B. Do not lie
C. Either A or B
D. None of these
Answer : B
5. The forces, whose lines of action are parallel to each other and act in the same directions, are known as
A. Coplanar concurrent forces
B. Coplanar non-concurrent forces
C. Like parallel forces
D. Unlike parallel forces
Answer : C
6. The unit of moment of inertia of an area is
A. kg-m2
B. kg-m-s2
C. kg/m2
D. m4
Answer : D
7. The M.I. of hollow circular section about a central axis perpendicular to section as compared to its M.I. about horizontal axis is
A. Same
B. Double
C. Half
D. Four times
Answer : B
8. Which of the following are vector quantities?
A. Angular displacement
B. Angular velocity
C. Angular acceleration
D. All of these
Answer : D
9. Moment of inertia of a triangular section of base (b) and height (h) about an axis passing through its C.G. and parallel to the base, is
A. bh3/4
B. bh3/8
C. bh3/12
D. bh3/36
Answer : D
10. A machine having an efficiency less than 50%, is known as
A. Reversible machine
B. Non-reversible machine
C. Neither reversible nor non-reversible machine
D. Ideal machine
Answer : B
11. The moment of inertia of a solid cone of mass m and base radius r about its vertical axis is
A. 3mr2/5
B. 3mr2/10
C. 2mr2/5
D. 4mr2/5
Answer : B
12. The time of flight (t) of a projectile on a horizontal plane is given by
A. t = 2u. sin?/g
B. t = 2u. cos?/g
C. t = 2u. tan?/g
D. t = 2u/g.sin?
Answer : A
13. The product of either force of couple with the arm of the couple is called
A. Resultant couple
B. Moment of the forces
C. Resulting couple
D. Moment of the couple
Answer : D
14. If three forces acting in one plane upon a rigid body, keep it in equilibrium, then they must either
A. Meet in a point
B. Be all parallel
C. At least two of them must meet
D. All the above are correct
Answer : D
15. Moment of inertia of a hollow circular section, as shown in the below figure about an axis perpendicular to the section, is __________ than that about X-X axis.
A. Two times
B. Same
C. Half
D. None of these
Answer : A
16. If a number of forces are acting at a point, their resultant is given by
A. (?V)2 + (?H)2
B. ?[(?V)2 + (?H)2]
C. (?V)2 +(?H)2 +2(?V)(?H)
D. ?[(?V)2 +(?H)2 +2(?V)(?H)]
Answer : B
17. Whenever a force acts on a body and the body undergoes a displacement, then
A. Work is said to be done
B. Power is being transmitted
C. Body has kinetic energy of translation
D. None of these
Answer : A
18. The maximum efficiency of a screw jack is
A. (1 - sin?)/(1 + sin?)
B. (1 + sin?)/(1 - sin?)
C. (1 - tan?)/(1 + tan?)
D. (1 + tan?)/(1 - tan?)
Answer : A
19. Center of percussion is
A. The point of C.G.
B. The point of metacenter
C. The point of application of the resultant of all the forces tending to cause a body to rotate about a certain axis
D. Point of suspension
Answer : C
20. The law of motion involved in the recoil of gun is
A. Newton's first law of motion
B. Newton's second law of motion
C. Newton's third law of motion
D. None of these
Answer : C
21. The moment of inertia of a thin disc of mass m and radius r, about an axis through its centre of gravity and perpendicular to the plane of the disc is
A. mr2/2
B. mr2/4
C. mr2/6
D. mr2/8
Answer : A
22. Th centre of gravity of a trapezium with parallel sides a and b lies at a distance of y from the base b, as shown in the below figure. The value of y is
A. h [(2a + b)/(a + b)]
B. (h/2) [(2a + b)/(a + b)]
C. (h/3) [(2a + b)/(a + b)]
D. (h/3) [(a + b)/(2a + b)]
Answer : C
23. In the shown figure, if the angle of inclination of the plane is increased, then acceleration of the system will
A. Increase
B. Decrease
C. Remain the same
D. None of these
Answer : B
24. The moment of the force P about O as shown in the below figure is
A. P × OA
B. P × OB
C. P × OC
D. P × AC
Answer : C
25. If two bodies having masses m1 and m2 (m1>m2) have equal kinetic energies, the momentum of body having mass m1 is _________ the momentum of body having mass m2.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer : C
26. In order to determine the effects of a force, acting on a body, we must know
A. Magnitude of the force
B. Line of action of the force
C. Nature of the force i.e. whether the force is push or pull
D. All of the above
Answer : D
27. A framed structure is perfect, if the number of members are __________ (2j - 3), where j is the number of joints.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer : A
28. If a number of coplanar forces acting at a point be in equilibrium, the sum of clockwise moments must be __________ the sum of anticlockwise moments, about any point.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer : A
29. A spherical body is symmetrical about its perpendicular axis. According to Routh's rule, the moment of inertia of a body about an axis passing through its centre of gravity is (where, M = Mass of the body, and S = Sum of the squares of the two semi-axes.)
A. MS/3
B. MS/4
C. MS/5
D. None of these
Answer : C
30. Coplanar concurrent forces are those forces which
A. Meet at one point, but their lines of action do not lie on the same plane
B. Do not meet at one point and their lines of action do not lie on the same plane
C. Meet at one point and their lines of action also lie on the same plane
D. Do not meet at one point, but their lines of action lie on the same plane
Answer : C
31. The centre of percussion of a solid cylinder of radius r resting on a horizontal plane will be
A. r/2
B. 2r/3
C. r/A
D. 3r/2
Answer : D
32. Moment of inertia of a rectangular section having width (b) and depth (d) about an axis passing through its C.G. and parallel to the width (b), is
A. db³/12
B. bd³/12
C. db³/36
D. bd³/36
Answer : B
33. The maximum frictional force which comes into play when a body just begins to slide over another surface is called
A. Limiting friction
B. Sliding friction
C. Rolling friction
D. Kinematic friction
Answer : A
34. Which of the following is the locus of a point that moves in such a manner that its distance from a fixed point is equal to its distance from a fixed line multiplied by a constant greater than one
A. Ellipse
B. Hyperbola
C. Parabola
D. Circle
Answer : B
35. The periodic time (T) is given by (where, ? = Angular velocity of particle in rad/s.)
A. ?/2?
B. 2?/?
C. 2? × ?
D. ?/?
Answer : B
36. The law of the machine is (where P = Effort applied to lift the load, m = A constant which is equal to the slope of the line, W = Load lifted, and C = Another constant which represents the machine friction.)
A. P = mW - C
B. P = m/W + C
C. P = mW + C
D. P = C - mW
Answer : C
37. The efficiency of a screw jack is maximum, when (where ? = Helix angle, and ? = Angle of friction.)
A. ? = 45° + ?/2
B. ? = 45° - ?/2
C. ? = 90° + ?
D. ? = 90° - ?
Answer : B
38. The resultant of two equal forces P making an angle ?, is given by
A. 2P sin?/2
B. 2P cos?/2
C. 2P tan?/2
D. 2P cot?/2
Answer : B
39. Moment of inertia of a triangular section of base (b) and height (h) about an axis through its base, is
A. bh3/4
B. bh3/8
C. bh3/12
D. bh3/36
Answer : C
40. The moment of inertia of a square of side a about its diagonal is
A. a2/8
B. a3/12
C. a4/12
D. a4/16
Answer : C
41. Coplanar non-concurrent forces are those forces which __________ at one point, but their lines of action lie on the same plane.
A. Meet
B. Do not meet
C. Either A or B br>D. None of these
Answer : B
42. The velocity ratio of a simple wheel and axle with D and d as the diameters of effort wheel and load axle, is
A. D + d
B. D - d
C. D × d
D. D / d
Answer : D
43. The velocity ratio for the third system of pulleys is
A. n
B. n²
C. 2n
D. 2n - 1
Answer : D
44. Centre of gravity of a thin hollow cone lies on the axis at a height of
A. One-fourth of the total height above base
B. One-third of the total height above base
C. One-half of the total height above base
D. Three-eighth of the total height above the base
Answer : B
45. The ratio of limiting friction and normal reaction is known as
A. Coefficient of friction
B. Angle of friction
C. Angle of repose
D. Sliding friction
Answer : A
46. The rate of change of displacement of a body is called
A. Velocity
B. Acceleration
C. Momentum
D. None of these
Answer : A
47. Which of the following is not the unit of pressure?
A. kg/cm
B. Bar
C. Atmosphere
D. Newton
Answer : D
48. One end of a helical spring is fixed while the other end carries the load W which moves with simple harmonic motion. The frequency of motion is given by (where ? = Deflection of the spring.)
A. 2?. ?(g/?)
B. 1/2?. ?(g/?)
C. 2?. ?(?/g)
D. 1/2?. ?(?/g)
Answer : B
49. If n = number of members and y = number of joints, then for a perfect frame, n = ?
A. 1/2
B. 2/3
C. 3/2
D. 2/4
Answer : B
50. If the masses of both the bodies, as shown in the below figure, are doubled, then the acceleration in the string will be
A. Same
B. Half
C. Double
D. None of these
Answer : A
Downlaod Engineering Mechanics MCQ PDF

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