1000+ Engineering Mechanics Multiple Choice Question Answer [Solved]

1. 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

2. 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

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

4. According to parallel axis theorem, the moment of inertia of a section about an axis parallel to the axis through centre of gravity (i.e. I_P) is given by(where, A = Area of the section, I_G = Moment of inertia of the section about an axis passing through its C.G., and h = Distance between C.G. and the parallel axis.)
A. I_P = I_G + Ah²
B. I_P = I_G - Ah²
C. I_P = I_G / Ah²
D. I_P = Ah² / I_G
Answer : A

5. The moment of a force
A. Is the turning effect produced by a force, on the body, on which it acts
B. Is equal to the product of force acting on the body and the perpendicular distance of a point and the line of action of the force
C. Is equal to twice the area of the triangle, whose base is the line representing the force and whose vertex is the point, about which the moment is taken
D. All of the above
Answer : D

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. 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

8. The maximum frictional force, which comes into play, when a body just begins to slide over the surface of the other body, is known as
A. Static friction
B. Dynamic friction
C. Limiting friction
D. Coefficient of friction
Answer : C

9. The point, through which the whole weight of the body acts, irrespective of its position, is known as
A. Moment of inertia
B. Centre of gravity
C. Centre of percussion
D. Centre of mass
Answer : B

10. 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

11. 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

12. A circular hole of 50 mm diameter is cut out from a circular disc of 100 mm diameter as shown in the below figure. The centre of gravity of the section will lie
A. In the shaded area
B. In the hole
C. At O
D. None of these
Answer : A

13. 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

14. 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

15. The rate of doing work is known as
A. Potential energy
B. Kinetic energy
C. Power
D. None of these
Answer : C

16. Which of the following is not the unit of distance?
A. Angstrom
B. Light year
C. Micron
D. Milestone
Answer : D

17. 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

18. The ideal angle of banking provided on the curves on roads depends upon
A. Weight of the vehicle
B. (Velocity)2 of the vehicle
C. Nature of the road surface
D. Coefficient of friction between the road and vehicle contact point
Answer : B

19. Moment of inertia of a hollow circular section, as shown in the below figure about X-axis, is
A. ?/16 (D² - d²)
B. ?/16 (D³ - d³)
C. ?/32 (D? - d?)
D. ?/64 (D? - d?)
Answer : D

20. The velocity ratio of a differential pulley block with D and d as the diameters of larger and smaller pulley, is
A. D/(D - d)
B. D/(D + d)
C. 2D/(D - d)
D. 2D/(D + d)
Answer : C

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

22. The friction experienced by a body, when in motion, is known as
A. Rolling friction
B. Dynamic friction
C. Limiting friction
D. Static friction
Answer : B

23. The horizontal range of a projectile (R) is given by
A. R = u² cos2?/g
B. R = u² sin2?/g
C. R = u² cos?/g
D. R = u² sin?/g
Answer : B

24. The total energy possessed by a system of moving bodies
A. Is constant at every instant
B. Varies from point to point
C. Is maximum in the start and minimum at the end
D. Is minimum in the start and maximum at the end
Answer : A

25. 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

26. Which one of the following statements is not correct?
A. The tangent of the angle of friction is equal to coefficient of friction
B. The angle of repose is equal to angle of friction
C. The tangent of the angle of repose is equal to coefficient of friction
D. The sine of the angle of repose is equal to coefficient to friction
Answer : D

27. The velocity ratio for the first system of pulleys is (where n is the number of pulleys.)
A. n
B. n²
C. 2n
D. 2n - 1
Answer : C

28. 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

29. The friction experienced by a body, when at rest, is known as
A. Static friction
B. Dynamic friction
C. Limiting friction
D. Coefficient of friction
Answer : A

30. 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

31. The velocity of a particle moving with simple harmonic motion is __________ at the mean position.
A. Zero
B. Minimum
C. Maximum
D. None of these
Answer : C

32. 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

33. The principle of transmissibility of forces states that, when a force acts upon a body, its effect is
A. Same at every point on its line of action
B. Different at different points on its line of action
C. Minimum, if it acts at the centre of gravity of the body
D. Maximum, if it acts at the centre of gravity of the body
Answer : C

34. The maximum mechanical advantage of a lifting machine is
A. 1 + m
B. 1 - m
C. 1 / m
D. m
Answer : C

35. A body of mass m moving with a constant velocity v strikes another body of same mass moving with same velocity but in opposite direction. The common velocity of both the bodies after collision is
A. v
B. 2v
C. 4v
D. 8v
Answer : B

36. If a number of forces are acting at a point, their resultant will be inclined at an angle ? with the horizontal, such that
A. tan? = ?H/?V
B. tan? = ?V/?H
C. tan? = ?V × ?H
D. tan? = ?(?V + ?H)
Answer : B

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

38. 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

39. The centre of gravity of a quadrant of a circle lies along its central radius (r) at a distance of
A. 0.5r
B. 0.6 r
C. 0.7 r
D. 0.8 r
Answer : B

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

41. A single force and a couple acting in the same plane upon a rigid body
A. Balance each other
B. Cannot balance each other C. Produce moment of a couple
D. Are equivalent
Answer : B

42. If P is the force acting on the body, m is the mass of the body and a is the acceleration of the body, then according to Newton's second law of motion,
A. P + m.a = 0
B. P - m.a = 0
C. P × m.a = 0
D. P/m.a = 0
Answer : B

43. The range of projectile will be maximum for a given velocity of projectile, when the angle of projection (?) is
A. ?/2
B. 30° + ?/2
C. 45° + ?/2
D. 60° + ?/2
Answer : C

44. 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

45. The velocity of a body on reaching the ground from a height h, is
A. 2.?(gh)
B. ?(gh)
C. ?(2gh)
D. 2g.?h
Answer : C

46. 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

47. The coefficient of restitution for inelastic bodies is
A. Zero
B. One
C. Between zero and one
D. More than one
Answer : A

48. The 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

49. One kg force is equal to
A. 7.8 N
B. 8.9 N
C. 9.8 N
D. 12 N
Answer : C

50. 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