1000+ Engineering Mechanics MCQ for FCI Recruitment [Solved]

1. Which of the following statement is correct in connection with projectiles?
A. A path, traced by a projectile in the space, is known as trajectory.
B. The velocity, with which a projectile is projected, is known as the velocity of projection.
C. The angle, with the horizontal, at which a projectile is projected, is known as angle of projection.
D. All of the above
Answer : D

2. The resultant of two forces P and Q (such that P > Q) acting along the same straight line, but in opposite direction, is given by
A. P + Q
B. P - Q
C. P / Q
D. Q / P
Answer : B

3. The C.G. of a solid hemisphere lies on the central radius 3r
A. At distance from the plane base 3r
B. At distance from the plane base 3r
C. At distance from the plane base 3r
D. At distance from the plane base
Answer : D

4. Dynamic friction as compared to static friction is
A. Same
B. More
C. Less
D. May be less of more depending on nature of surfaces and velocity
Answer : C

5. A body moves, from rest with a constant acceleration of 5 m per sec. The distance covered in 5 sec is most nearly
A. 38 m
B. 62.5 m
C. 96 m
D. 124 m
Answer : B

6. The angle which an inclined plane makes with the horizontal when a body placed on it is about to move down is known as angle of
A. Friction
B. Limiting friction
C. Repose
D. Kinematic friction
Answer : C

7. 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

8. From a circular plate of diameter 6 cm is cut out a circle whose diameter is a radius of the plate. Find the e.g. of the remainder from the centre of circular plate
A. 0.5 cm
B. 1.0 cm
C. 1.5 cm
D. 2.5 cm
Answer : A

9. The process of finding out the resultant force is called __________ of forces.
A. Composition
B. Resolution
C. Decomposition
D. None of these
Answer : A

10. According to principle of moments
A. If a system of coplanar forces is in equilibrium, then their algebraic sum is zero
B. If a system of coplanar forces is in equilibrium, then the algebraic sum of their moments about any point in their plane is zero
C. The algebraic sum of the moments of any two forces about any point is equal to moment of the resultant about the same point
D. Positive and negative couples can be balanced
Answer : B

11. The unit of force in S.I. units is
A. kilogram
B. Newton
C. Watt
D. Dyne
Answer : B

12. A force is completely defined when we specify
A. Magnitude
B. Direction
C. Point of application
D. All of the above
Answer : D

13. The ratio of static friction to dynamic friction is always
A. Equal to one
B. Less than one
C. Greater than one
D. None of these
Answer : C

14. 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

15. 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

16. Which of the following statement is correct?
A. The kinetic energy of a body during impact remains constant.
B. The kinetic energy of a body before impact is equal to the kinetic energy of a body after impact.
C. The kinetic energy of a body before impact is less than the kinetic energy of a body after impact.
D. The kinetic energy of a body before impact is more than the kinetic energy of a body after impact.
Answer : D

17. Which of the following is not a vector quantity?
A. Weight
B. Velocity
C. Acceleration
D. Force
Answer : A

18. Centre of gravity of a solid cone lies on the axis at the height
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 : A

19. The moment of inertia of a square of side (a) about an axis through its centre of gravity is
A. a⁴/4
B. a⁴/8
C. a⁴/12
D. a⁴/36
Answer : C

20. A trolley wire weighs 1.2 kg per meter length. The ends of the wire are attached to two poles 20 meters apart. If the horizontal tension is 1500 k find the dip in the middle of the span
A. 2.5 cm
B. 3.0 cm
C. 4.0 cm
D. 5.0 cm
Answer : C

21. A framed structure is perfect if it contains members equal to
A. 2n³
B. 2n
C. n²
D. 3n² Where n = number of joints in a frame
Answer : A

22. The velocity ratio in case of an inclined plane inclined at angle ? to the horizontal and weight being pulled up the inclined plane by vertical effort is
A. sin?
B. cos?
C. tan?
D. cosec?
Answer : A

23. The range of a projectile is maximum, when the angle of projection is
A. 30°
B. 45°
C. 60°
D. 90°
Answer : B

24. Which of the following is not the unit of pressure?
A. kg/cm
B. Bar
C. Atmosphere
D. Newton
Answer : D

25. 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

26. The C.G. of a right circular solid cone of height h lies at the following distance from the base
A. h/2
B. J/3
C. h/6
D. h/4
Answer : D

27. The centre of gravity of an isosceles triangle with base (p) and sides (q) from its base is
A. [?(4p² - q²)]/6
B. (4p² - q²)/6
C. (p² - q²)/4
D. (p² + q²)/4
Answer : A

28. The resultant of two forces P and Q acting at an angle ? is
A. ?(P² + Q² + 2PQ sin?)
B. ?(P² + Q² + 2PQ cos?)
C. ?(P² + Q² - 2PQ cos?)
D. ?(P² + Q² - 2PQ tan?)
Answer : B

29. One joule is equal to
A. 0.1 N-m
B. 1 N-m
C. 10 N-m
D. 100 N-m
Answer : B

30. Two blocks A and B of masses 150 kg and 50 kg respectively are connected by means of a string as shown in the below figure. The tension in all the three strings __________ be same.
A. Will
B. Will not
C. Either A or B
D. None of these
Answer : A

31. Efficiency of a screw jack is given by (where ? = Helix angle, and ? = Angle of friction.)
A. tan(? + ?)/tan?
B. tan?/tan (? + ?)
C. tan(? - ?)/tan?
D. None of these
Answer : B

32. When a body of mass m attains a velocity v from rest in time t, then the kinetic energy of translation is
A. mv²
B. mgv²
C. 0.5 mv²
D. 0.5 mgv²
Answer : C

33. A machine having an efficiency greater than 50%, is known as
A. Reversible machine
B. Non-reversible machine
C. Neither reversible nor non-reversible machine
D. Ideal machine
Answer : A

34. Work done is said to be zero, when
A. Some force acts on a body, but displacement is zero
B. No force acts on a body but some displacement takes place
C. Either (A) or (B)
D. None of the above
Answer : C

35. The moment of inertia of a thin spherical shell of mass m and radius r, about its diameter is
A. mr²/3
B. 2mr²/3
C. 2mr²/5
D. 3mr²/5
Answer : B

36. 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

37. When two elastic bodies collide with each other,
A. The two bodies will momentarily come to rest after collision
B. The two bodies tend to compress and deform at the surface of contact
C. The two bodies begin to regain their original shape
D. All of the above
Answer : D

38. A smooth cylinder lying on its convex surface remains in __________ equilibrium.
A. Stable
B. Unstable
C. Neutral
D. None of these
Answer : B

39. The necessary condition for forces to be in equilibrium is that these should be
A. Coplanar
B. Meet at one point
C. Both (A) and (B) above
D. All be equal
Answer : C

40. Which of the following is not a scalar quantity?
A. Mass
B. Volume
C. Density
D. Acceleration
Answer : D

41. The moment of inertia of a thin rod of mass m and length l, about an axis through its centre of gravity and perpendicular to its length is
A. ml²/4
B. ml²/ 6
C. ml²/8
D. ml²/12
Answer : D

42. 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

43. 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 depth (d), is
A. db³/12
B. bd³/12
C. db³/36
D. bd³/36
Answer : A

44. A pair of smith's tongs is an example of the lever of
A. Zeroth order
B. First order
C. Second order
D. Third order
Answer : C

45. The power developed by a body acted upon by a torque T Newton metre (N - m) and revolving at ? radian/s is given by
A. T.? (in watts)
B. T.?/60 (in watts)
C. T.?/75 (in kilowatts)
D. T.?/4500 (in kilowatts)
Answer : A

46. A heavy string attached at two ends at same horizontal level and when central dip is very small approaches the following curve
A. Circular arc
B. Parabola
C. Hyperbola
D. Elliptical
Answer : B

47. Which of the following is a scalar quantity?
A. Force
B. Speed
C. Velocity
D. Acceleration
Answer : B

48. A differential pulley block has larger and smaller diameters of 100 mm and 80 mm respectively. Its velocity ratio is
A. 5
B. 10
C. 20
D. 40
Answer : B

49. The unit of power in S.I. units is
A. Horsepower
B. Joule
C. Watt
D. kg-m
Answer : C

50. Static friction is always __________ dynamic friction.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer : C