Engineering Mechanics 1000+ MCQ with answer for ESIC

1. The resolved part of the resultant of two forces inclined at an angle ? in a given direction is equal to
A. The algebraic sum of the resolved parts of the forces in the given direction
B. The sum of the resolved parts of the forces in the given direction
C. The difference of the forces multiplied by the cosine of ?
D. The sum of the forces multiplied by the sine of ?
Answer : A

2. During elastic impact, the relative velocity of the two bodies after impact is __________ the relative velocity of the two bodies before impact.
A. Equal to
B. Equal and opposite to
C. Less than
D. Greater than
Answer : B

3. An ideal machine is one whose efficiency is
A. Between 60 and 70 %
B. Between 70 and 80 %
C. Between 80 and 90 %
D. 100 %
Answer : D

4. A smooth cylinder lying on a __________ is in neutral equilibrium.
A. Curved surface
B. Convex surface
C. Horizontal surface
D. None of these
Answer : C

5. 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

6. The linear velocity of a body rotating at ? rad/s along a circular path of radius r is given by
A. ?/r
B. ?.r
C. ?²/r
D. ?².r
Answer : B

7. The centre of gravity of a semi-circle lies at a distance of __________ from its base measured along the vertical radius.
A. 3r/ 8
B. 4r/ 3?
C. 8r/3
D. 3r/4?
Answer : B

8. If the gravitational acceleration at any place is doubled, then the weight of a body will be
A. g/2
B. g
C. ?2.g
D. 2g
Answer : D

9. 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

10. A flywheel on a motor goes from rest to 1000 rpm in 6 sec. The number of revolutions made is nearly equal to
A. 25
B. 50
C. 100
D. 250
Answer : B

11. When a person, on a bicycle, drives round a curve, he has to lean __________ to maintain equilibrium.
A. Inward
B. Outward
C. Towards front
D. Towards back
Answer : A

12. 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

13. 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

14. The slope on the road surface generally provided on the curves is known as
A. Angle of friction
B. Angle of repose
C. Angle of banking
D. None of these
Answer : C

15. 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

16. 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

17. 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

18. 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

19. 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

20. The efficiency of a screw jack ismaximum, when (where ? = Helix angle, and ? = Angle of friction.)
A. ? = 45° + ?/2
B. ? = 45° - ?/2
C. ? = 90° + ?
D. ? = 90° - ?
Answer : B

21. 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

22. 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

23. 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

24. According to law of triangle of forces
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 : C

25. Non-coplanar non-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. Do not meet at one point but their lines of action lie on the same plane
D. None of the above
Answer : B

26. The range of projectile (R) on an upward inclined plane is
A. g. cos² ?/2u². sin (? + ?). cos ?
B. 2u². sin (? + ?). cos ?/g. cos² ?
C. g. cos² ?/2u². sin (? - ?). cos ?
D. 2u². sin (? - ?). cos ?/g. cos² ?
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. Three forces acting on a rigid body are represented in magnitude, direction and line of action by the three sides of a triangle taken in order. The forces are equivalent to a couple whose moment is equal to
A. Area of the triangle
B. Twice the area of the triangle
C. Half the area of the triangle
D. None of these
Answer : B

29. A sample of metal weighs 219 gms in air, 180 gms in water, 120 gms in an unknown fluid. Then which is correct statement about density of metal
A. Density of metal can't be determined
B. Metal is twice as dense as water
C. Metal will float in water
D. Metal is twice as dense as unknown fluid
Answer : A

30. 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

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

32. 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

33. The static friction
A. Bears a constant ratio to the normal reaction between the two surfaces
B. Is independent of the area of contact, between the two surfaces
C. Always acts in a direction, opposite to that in which the body tends to move
D. All of the above
Answer : D

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

35. A redundant frame is also called __________ frame.
A. Perfect
B. Imperfect
C. Deficient
D. None of these
Answer : B

36. The loss of kinetic energy during inelastic impact, is given by (where m₁ = Mass of the first body, m₂ = Mass of the second body, and u₁ and u₂ = Velocities of the first and second bodies respectively.)
A. [m? m?/2(m? + m?)] (u? - u?)²
B. [2(m? + m?)/m? m?] (u? - u?)²
C. [m? m?/2(m? + m?)] (u?² - u?²)
D. [2(m? + m?)/m? m?] (u?² - u?²)
Answer : A

37. The maximum acceleration of a particle moving with simple harmonic motion is
A. ?
B. ?r
C. ?²r
D. ?/r
Answer : C

38. 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

40. 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

41. 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

42. 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

43. The possible loading in various members of framed structures are
A. Compression or tension
B. Buckling or shear
C. Shear or tension
D. All of the above
Answer : A

44. 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

45. Varingon's theorem of moments states that 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 : D

46. 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

47. 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

48. 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

49. 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
D. None of these
Answer : B

50. 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