Engineering Mechanics 1000+ MCQ with answer for SSC CGL

1. 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

2. 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

3. 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

4. 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

5. The unit of moment of inertia of an area is
A. kg-m²
B. kg-m-s²
C. kg/m²
D. m⁴
Answer : D

6. 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

7. 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

8. 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

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

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

11. 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

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

13. 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

14. 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

15. The moment of inertia of a solid sphere of mass m and radius r is
A. 2mr²/3
B. 2mr²/5
C. mr²
D. mr²/2
Answer : B

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

17. 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

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

19. In the lever of third order, load W, effort P and fulcrum F are oriented as follows
A. W between P and F
B. F between W and P
C. P between W and F
D. W, P and F all on one side
Answer : A

20. A framed structure, as shown in the below figure, is a
A. Perfect frame
B. Deficient frame
C. Redundant frame
D. None of the above
Answer : A

21. The force applied on a body of mass 100 kg to produce an acceleration of 5 m/s², is
A. 20 N
B. 100 N
C. 500 N
D. None of these
Answer : C

22. The angle between two forces when the resultant is maximum and minimum respectively are:
A. 0° and 180°
B. 180° and 0°
C. 90° and 180°
D. 90° and 0°
Answer : A

23. The velocity ratio of a single purchase crab winch can be increased by
A. Increasing the length of the handle
B. Increasing the radius of the load drum C. Increasing the number of teeth of the pinion
D. All of the above
Answer : A

24. The efficiency of a lifting machine is the ratio of
A. Output to the input
B. Work done by the machine to the work done on the machine
C. Mechanical advantage to the velocity ratio
D. All of the above
Answer : D

25. 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

26. The periodic time (T) is given by (where, ? = Angular velocity of particle in rad/s.)
A. ?/2?
B. 2?/?
C. 2? × ?
D. ?/?
Answer : B

27. The wheels of a moving car possess
A. Potential energy only
B. Kinetic energy of translation only
C. Kinetic energy of rotation only
D. Kinetic energy of translation and rotation both
Answer : D

28. Mass moment of inertia of a uniform thin rod of mass M and length (l) about its mid-point and perpendicular to its length is
A. (2/3) Ml²
B. (1/3) Ml²
C. (3/4) Ml²
D. (1/12) Ml²
Answer : D

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

30. 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

31. 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

32. In determining stresses in frames by methods of sections, the frame is divided into two parts by an imaginary section drawn in such a way as not to cut more than
A. Two members with unknown forces of the frame
B. Three members with unknown forces of the frame
C. Four members with unknown forces of the frame
D. Three members with known forces of the frame
Answer : B

33. 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

34. The velocity ratio of a first system of pulleys with 4 pulleys is
A. 4
B. 8
C. 16
D. 20
Answer : C

35. Which of the following do not have identical dimensions?
A. Momentum and impulse
B. Torque and energy
C. Torque and work
D. Moment of a force and angular momentum.
Answer : D

36. The time of flight (t) of a projectile on a horizontal plane is given by
A. t = 2u. sin?/g
B. t = 2u. cos?/g
C. t = 2u. tan?/g
D. t = 2u/g.sin?
Answer : A

37. The maximum height of a projectile on a horizontal plane, is
A. u² sin²?/2g
B. u² cos²?/2g
C. u² sin²?/g
D. u² cos²?/g
Answer : A

38. 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

39. 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

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

41. 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

42. 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

43. 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

44. If the masses of both the bodies, as shown in the below figure, are doubled, then the acceleration in the string will be
A. Same
B. Half
C. Double
D. None of these
Answer : A

45. 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

46. If a number of forces act simultaneously on a particle, it is possible
A. Not a replace them by a single force
B. To replace them by a single force
C. To replace them by a single force through C.G.
D. To replace them by a couple
Answer : B

47. The bodies which rebound after impact are called
A. Inelastic bodies
B. Elastic bodies
C. Neither elastic nor inelastic bodies
D. None of these
Answer : B

48. 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

49. 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

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