1000+ Engineering Mechanics MCQ for IBPS SO [Solved]

1. A lead ball with a certain velocity is made to strike a wall, it falls down, but rubber ball of same mass and with same velocity strikes the same wall, it rebounds. Select the correct reason from the following:
A. Both the balls undergo an equal change in momentum
B. The change in momentum suffered by rubber ball is more than the lead ball
C. The change in momentum suffered by rubber ball is less than the lead ball
D. None of the above
Answer : B

2. 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

3. Non-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 : A

4. The unit of angular acceleration is
A. N-m
B. m/s
C. m/s2
D. rad/s2
Answer : D

5. Moment of inertia of a triangular section of base (b) and height (h) about an axis passing through its vertex and parallel to the base, is __________ than that passing through its C.G. and parallel to the base.
A. Nine times
B. Six times
C. Four times
D. Two times
Answer : A

6. The centre of gravity of a right circular solid cone is at a distance of __________ from its base, measured along the vertical axis. (where h = Height of a right circular solid cone.)
A. h/2
B. h/3
C. h/4
D. h/6
Answer : C

7. Lami's theorem states that
A. Three forces acting at a point will be in equilibrium
B. Three forces acting at a point can be represented by a triangle, each side being proportional to force
C. If three forces acting upon a particle are represented in magnitude and direction by the sides of a triangle, taken in order, they will be in equilibrium
D. If three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two
Answer : D

8. 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

9. 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

10. The length of a second's pendulum is
A. 94.9 cm
B. 99.4 cm
C. 100 cm
D. 101 cm
Answer : B

11. 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

12. Kinetic friction is the
A. Tangent of angle between normal reaction and the resultant of normal reaction and the limiting friction
B. Ratio of limiting friction and normal reaction
C. The friction force acting when the body is just about to move
D. The friction force acting when the body is in motion
Answer : D

13. A pendulum which executes one beat per second is known as
A. Simple pendulum
B. Compound pendulum
C. Torsional pendulum
D. Second's pendulum
Answer : D

14. The angular velocity (in rad/s) of a body rotating at N revolutions per minute is
A. ?N/60
B. ?N/180
C. 2?N/60
D. 2?N/180
Answer : C

15. Moment of inertia is the
A. Second moment of force
B. Second moment of area
C. Second moment of mass
D. All of these
Answer : D

16. On a ladder resting on smooth ground and leaning against vertical wall, the force of friction will be
A. Towards the wall at its upper end
B. Away from the wall at its upper end
C. Upwards at its upper end
D. Downwards at its upper end
Answer : C

17. 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

18. 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

19. 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

20. 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

21. 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

22. 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

23. The forces which do not meet at one point and their lines of action do not lie on the same plane are known as
A. Coplanar concurrent forces
B. Coplanar non-concurrent forces
C. Non-coplanar concurrent forces
D. None of these
Answer : D

24. A block of mass 20 kg lying on a rough horizontal plane is connected by a light string passing over a smooth pulley to another mass 5 kg, which can move freely in the Vertical direction, as shown in the below figure. The tension in the string will __________ with the increase in coefficient of friction.
A. Increase
B. Decrease
C. Not be effected
D. None of these
Answer : A

25. Coulomb friction is the friction between
A. Bodies having relative motion
B. Two dry surfaces
C. Two lubricated surfaces
D. Solids and liquids
Answer : A

26. 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

27. The unit of angular velocity is
A. m/min
B. rad/s
C. Revolutions/min
D. Both (B) and (C)
Answer : D

28. The units of moment of inertia of mass are
A. kg-m²
B. m²/kg.
C. kg/m²
D. kg/m
Answer : A

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

30. 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

31. 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

32. When the lift is moving upwards with some acceleration, the pressure exerted by a man is __________ to its acceleration.
A. Directly proportional
B. Inversely proportional
C. Cube root
D. None of these
Answer : A

33. The velocity ratio of a differential wheel and axle with D as the diameter of effort wheel and d1 and d2 as the diameters of larger and smaller axles respectively, is
A. D/(d? + d?)
B. D/(d? - d?)
C. 2D/(d? + d?)
D. 2D/(d? - d?)
Answer : D

34. If a suspended body is struck at the centre of percussion, then the pressure on die axis passing through the point of suspension will be
A. Maximum
B. Minimum
C. Zero
D. Infinity
Answer : C

35. The periodic time of a particle with simple harmonic motion is __________ proportional to the angular velocity.
A. Directly
B. Inversely
C. Square root
D. None of these
Answer : B

36. 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

37. 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

38. If a rigid body is in equilibrium under the action of three forces, then
A. These forces are equal
B. The lines of action of these forces meet in a point
C. The lines of action of these forces are parallel
D. Both (B) and (C) above
Answer : D

39. Which of the following is an equation of linear motion? (where, u and v = Initial and final velocity of the body, a = Acceleration of the body, and s = Displacement of the body in time t seconds.)
A. v = u + a.t
B. s = u.t + ½ a.t²
C. v² = u² + 2a.s
D. All of these
Answer : D

40. If the body falls freely under gravity, then the gravitational acceleration is taken as
A. +8.9 m/s²
B. -8.9 m/s²
C. +9.8 m/s²
D. -9.8 m/s²
Answer : C

41. The matter contained in a body, is called
A. Impulsive force
B. Mass
C. Weight
D. Momentum
Answer : B

42. Two coplanar couples having equal and opposite moments
A. Balance each other
B. Produce a couple and an unbalanced force
C. Are equivalent
D. Cannot balance each other
Answer : D

43. 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

44. A weight of 1000 N can be lifted by an effort of 80 N. If the velocity ratio is 20, the machine is
A. Reversible
B. Non-reversible
C. Ideal
D. None of these
Answer : A

45. Joule is the unit of
A. Force
B. Work
C. Power
D. Velocity
Answer : B

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

47. The unit of work in S.I. units is
A. Newton
B. erg
C. kg-m
D. joule
Answer : D

48. 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

49. 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

50. 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