1000+ Engineering Mechanics Multiple Choice Question Answer [Solved]

1. Mass moment of inertia of a thin rod about its one end is __________ the mass moment of inertia of the same rod about its midpoint
A. Same as
B. Twice
C. Thrice
D. Four times
Answer : D

2. A framed structure is imperfect, if the numbers of members are __________ (2j - 3).
A. Equal to
B. Less than
C. Greater than
D. Either (B) or (C)
Answer : D

3. The weight of a body is due to
A. Gravitational pull exerted by the earth
B. Forces experienced by body in atmosphere
C. Force of attraction experienced by particles
D. Gravitational force of attraction towards the centre of the earth
Answer : D

4. The minimum force required to slide a body of weight W on a rough horizontal plane is
A. W sin?
B. W cos?
C. W tan?
D. None of these
Answer : C

5. 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

6. The motion of a wheel of a car is
A. Purely translation
B. Purely rotational
C. Combined translation and rotational
D. None of these
Answer : C

7. Frictional force encountered after commencement of motion is called
A. Limiting friction
B. Kinematic friction
C. Frictional resistance
D. Dynamic friction
Answer : D

8. The unit of force in S.I. system of units is
A. Dyne
B. Kilogram
C. Newton
D. Watt
Answer : C

9. In a framed structure, as shown in the below figure, the force in the member BC is
A. W/?3 (compression)
B. W/?3 (tension)
C. 2W/?3 (compression)
D. 2W/?3 (tension)
Answer : D

10. Pick up the incorrect statement from the following:
A. The C.G. of a circle is at its centre
B. The C.G. of a triangle is at the intersection of its medians
C. The C.G. of a rectangle is at the intersection of its diagonals
D. The C.G. of a semicircle is at a distance of r/2 from the centre
Answer : D

11. 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

12. One watt is equal to
A. 0.1 joule/s
B. 1 joule/s
C. 10 joules/s
D. 100 joules/s
Answer : B

13. The moment of inertia of a sphere of mass m and radius r, about an axis tangential to it, is
A. 2mr²/3
B. 2mr²/5
C. 7mr²/3
D. 7mr²/5
Answer : D

14. 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

15. A ladder is resting on a smooth ground and leaning against a rough vertical wall. The force of friction will act
A. Towards the wall at its upper end
B. Away from the wall at its upper end
C. Downward at its upper end
D. Upward at its upper end
Answer : D

16. The C.G. of a plane lamina will not be at its geometrical centre in the case of a
A. Right angled triangle
B. Equilateral triangle
C. Square
D. Circle
Answer : A

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. In order to completely specify angular displacement by a vector, it must fix
A. Direction of the axis of rotation
B. Magnitude of angular displacement
C. Sense of angular displacement
D. All of these
Answer : D

19. According to the law of moments, if a number of coplanar forces acting on a particle are in equilibrium, then
A. Their algebraic sum is zero
B. Their lines of action are at equal distances
C. The algebraic sum of their moments about any point in their plane is zero
D. The algebraic sum of their moments about any point is equal to the moment of their resultant force about the same point.
Answer : C

20. Two like parallel forces are acting at a distance of 24 mm apart and their resultant is 20 N. It the line of action of the resultant is 6 mm from any given force, the two forces are
A. 15 N and 5 N
B. 20 N and 5 N
C. 15 N and 15 N
D. None of these
Answer : A

21. 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

22. Least force required to draw a body up the inclined plane is W sin (plane inclination + friction angle) applied in the direction
A. Along the plane
B. Horizontally
C. Vertically
D. At an angle equal to the angle of friction to the inclined plane
Answer : D

23. The algebraic sum of moments of the forces forming couple about any point in their plane is
A. Equal to the moment of the couple
B. Constant
C. Both of above are correct
D. Both of above are wrong
Answer : A

24. In the shown figure, the tension (T) in the string will be
A. m?. m?. g/(m? + m?)
B. 2m?. m?. g/(m? + m?)
C. (m? + m?)/ m?. m?. g
D. (m? + m?)/2m?. m?. g
Answer : B

25. The energy possessed by a body, for doing work by virtue of its position, is called
A. Potential energy
B. Kinetic energy
C. Electrical energy
D. Chemical energy
Answer : A

26. A ladder is resting on a rough ground and leaning against a smooth vertical wall. The force of friction will act
A. Downward at its upper end
B. Upward at its upper end
C. Zero at its upper end
D. Perpendicular to the wall at its upper end
Answer : C

27. 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 kg 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

28. Which of the following is not the unit of work, energy and heat?
A. kcal
B. kg-m
C. kW-hr
D. h.p
Answer : D

29. 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

30. 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

31. Effect of a force on a body depends upon
A. Magnitude
B. Direction
C. Position or line of action
D. All of the above
Answer : D

32. 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

33. Moment of inertia of a hollow rectangular section as shown in the below figure about X-X axis, is
A. (BD³/12) - (bd³/12)
B. (DB³/12) - (db³/12)
C. (BD³/36) - (bd³/36)
D. (DB³/36) - (db³/36)
Answer : A

34. The Cartesian equation of trajectory is (where u = Velocity of projection, ? = Angle of projection, and x, y = Co-ordinates of any point on the trajectory after t seconds.)
A. y = (gx²/2u² cos²?) + x. tan?
B. y = (gx²/2u² cos²?) - x. tan?
C. y = x. tan? - (gx²/2u² cos²?)
D. y = x. tan? + (gx²/2u² cos²?)
Answer : C

35. 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

36. 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

37. 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

38. A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if
A. The floor is smooth, the wall is rough
B. The floor is rough, the wall is smooth
C. The floor and wall both are smooth surfaces
D. The floor and wall both are rough surfaces
Answer : C

39. A block of mass m1, placed on an inclined smooth plane is connected by a light string passing over a smooth pulley to mass m2, which moves vertically downwards as shown in the below figure. The tension in the string is
A. m₁/m₂
B. m₁. g. sin ?
C. m₁.m₂/m₁ + m₂
D. m₁. m₂.g (1 + sin ?)/(m₁ + m₂)
Answer : D

40. Two non-collinear parallel equal forces acting in opposite direction
A. Balance each other
B. Constitute a moment
C. Constitute a couple
D. Constitute a moment of couple
Answer : C

41. In a screw jack, the effort required to lower the load is __________ the effort required to raise the same load.
A. Less than
B. Equal to
C. More than
D. None of these
Answer : A

42. The coefficient of friction depends on
A. Area of contact
B. Shape of surfaces
C. Strength of surfaces
D. Nature of surface
Answer : D

43. The time of flight of a projectile on downward inclined plane depends upon
A. Angle of projection
B. Angle of inclination of the plane
C. Both (A) and (B)
D. None of these
Answer : C

44. Which of the following are vector quantities?
A. Angular displacement
B. Angular velocity
C. Angular acceleration
D. All of these
Answer : D

45. The centre of gravity a T-section 100 mm × 150 mm × 50 mm from its bottom is
A. 50 mm
B. 75 mm
C. 87.5 mm
D. 125 mm
Answer : C

46. A body will begin to move down an inclined plane if the angle of inclination of the plane is _________ the angle of friction.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer : C

47. 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

48. The units of moment of inertia of an area are
A. kg-m²
B. m?
C. kg/m²
D. m³
Answer : B

49. In the equation of virtual work, following force is neglected
A. Reaction of any smooth surface with which the body is in contact
B. Reaction of a rough surface of a body which rolls on it without slipping
C. Reaction at a point or an axis, fixed in space, around which a body is constrained to turn
D. All of the above
Answer : D

50. 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