engineering mechanics MCQs

Practise focused engineering mechanics questions with marked answers for exam preparation and subject revision.

engineering mechanics Mcqs
1. If three forces acting in different planes can be represented by a triangle, these will be in________________?
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A. unpredictable

B. full equilibrium

C. partial equilibrium

D. none of the above

E. non-equilibrium
2. According to principle of moments__________________?
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A. positive and negative couples can be balanced

B. if a system of coplanar forces is in equilibrium, then their algebraic sum is zero

C. if a system of coplanar forces is in equilibrium, then the algebraic sum of their moments about any point in their plane is zero

D. none of the above

E. the algebraic sum of the moments of any two forces about any point is equal to moment of theiwesultant about the same point

3. Friction force for dry surfaces. Friction force is________________?
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A. k up wrong statement?

B. proportional to normal load between the surfaces

C. none of the above is wrong statement

D. independent of the area of contact surfaces

E. dependent on the materials of contact surface

F. proportional to velocity of sliding
4. In ideal machines__________________?
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A. none of the above

B. mechanical advantage is unity

C. mechanical advantage is equal to velocity ratio

D. mechanical advantage is greater than velocity ratio

E. mechanical advantage is less than velocity ratio

5. The unit of force in S.I. units is________________?
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A. watt

B. dyne

C. newton

D. joule

E. kilogram

6. The necessary condition for forces to be in equilibrium is that these should be_________________?
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A. coplanar

B. meet at one point ;

C. both A. and B. above

D. all be equal

E. something else

7. The unit of work or energy in S.I. units is_______________?
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A. pascal

B. kilogram meter

C. newton

D. watt

E. joule
8. A number of forces acting at a point will be in equilibrium if_____________________?
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A. their total sum is zero

B. two resolved parts in two directions at right angles are equal

C. sum of resolved parts in any two per-pendicular directions are both zero

D. all of them are inclined equally

E. none of the above

9. According to principle of transmissibility of forces, the effect of a force upon a body is_________________?
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A. maximum when it acts at the center of gravity of a body

B. minimum when it acts at the C.G. of the body

C. the same at every point in its line of action

D. different at different points in its line of action

E. none of the above

10. 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___________________?
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A. parabola

B. hyperbola

C. circle

D. ellipse

E. none of the above

11. The product of either force of couple with the arm of the couple is called_________________?
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A. resulting couple

B. none of the above

C. moment of the couple

D. moment of the forces

E. resultant couple

12. The units of moment of inertia of an area are__________________?
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A. kg m2

B. kg/m4

C. kg/m2

D. m4

E. m3

13. A flywheel on a motor goes from rest to 1000 rpm in 6 sec. The number of revolutions made is nearly equal to___________________?
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A. 500

B. 50

C. 250

D. 25

E. 100

14. D Alemberts principle is used for______________________?
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A. determining stresses in the truss

B. reducing the problem of kinetics to equivalent statics problem

C. designing safe structures

D. stability of floating bodies

E. solving kinematic problems

15. Coefficient of friction is the_________________?
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A. angle between normal reaction and the resultant of normal reaction and the limiting friction

B. tangent of angle of repose

C. the friction force acting when the body is in motion

D. ratio of limiting friction and normal reaction

E. the friction force acting when the body is just about to move

16. Forces are called concurrent when their lines of action meet in________________?
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A. perpendicular planes

B. one point

C. different planes

D. plane

E. two points

17. According to Lamis theorem___________________?
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A. three forces acting at a point can be represented by a triangle, each side being proportional to force

B. none of the above

C. if three forces acting upon a particle are represented in magnitude and

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

E. three forces acting at a point will be in equilibrium

F. ection by the sides of a triangle, taken in order, they will be in equilibrium

18. The center of percussion of a solid cylinder of radius r resting on a horizontal plane will be_________________?
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A. r/2

B. 2r/3

C. 3r/2

D. 3r/A

E. r/A

19. Which of the following is a vector quantity___________________?
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A. momentum

B. energy

C. angle

D. mass

E. speed

20. The effort required to lift a load W on a screw jack with helix angle a and angle of friction <j) is equal to _________________?
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A. Wcos(a + )

B. Wsin(a + )

C. Wtan(a-)

D. Wtan(a + )

E. W (sin a + cos ).

21. The center of gravity of a uniform lamina lies at____________________?
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A. none of the above

B. the center of heavy portion

C. the bottom surface

D. the mid point of its axis

E. all of the above

22. A force is completely defined when we specify_______________?
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A. point of application

B. all of the above

C. direction

D. none of the above

E. magnitude

23. Which of the following do not have identical dimensions ?
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A. Torque and work

B. Torque and energy

C. Momentum and impulse

D. Moment of a force and angular momentum

E. Kinetic energy and potential energy

24. A semi-circular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi-cricular disc and horizontal surface is \i. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will____________________?
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A. slant up towards direction of pull

B. slant down towards direction of pull

C. none of the above

D. unpredictable

E. remain horizontal

25. A particle moves along a straight line such that distance (x) traversed in t seconds is given by x = t2 (t 4), the acceleration of the particle will be given by the equation __________________?
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A. 6f-4

B. 3t2-lt

C. 6f-8

D. 6t2-8t

E. 3t2+2t

26. The unit of power in S.I. units is______________?
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A. joule

B. pascal per sec

C. newton meter

D. watt

E. kilogram meter/sec

27. Forces are called coplanar when all of them acting on body lie in __________________?
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A. one point

B. different points

C. perpendicular planes

D. different planes

E. one plane
28. A body moves, from rest with a constant acceleration of 5 m per sec. The distance covered in 5 sec is most nearly_________________?
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A. 124 m

B. 96 m

C. 38 m

D. 240 m

E. 62.5 m
29. A body of weight W on inclined plane of a being pulled up by a horizontal force P will be on the point of motion up the plane when P is equal to________________?
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A. W

B. Wtan(a +

C. W\an(a-)

D. W sin (a + $)

E. Wtana

30. The M.I. of hollow circular section about a central axis perpendicular to section as compared to its M.I. about horizontal axis is__________________?
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A. one fourth

B. same

C. double

D. half

E. four times

31. Tangent of angle of friction is equal to__________________?
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A. kinetic friction

B. limiting friction

C. friction force

D. coefficient of friction

E. angle of repose

32. The C.G. of a right circular solid cone of height h lies at the following distance from the base______________?
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A. h/6

B. J/3

C. h/4

D. 3/i/5

E. h/2

33. The co-efficient of friction depends upon_______________?
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A. A. and B. above

B. nature of surfaces

C. ail of the above.

D. shape of the surfaces

E. area of contact

34. Coulomb friction is the friction between _________________?
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A. bodies having relative motion

B. two dry surfaces

C. electrically charged particles

D. solids and liquids

E. two lubricated surfaces

35. Which of the following is not the unit of energy_________________?
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A. kcal

B. kg m

C. wattr

D. watt hours

E. kg m x (m/sec)2

36. A single force and a couple acting in the same plane upon a rigid body_____________________?
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A. are equivalent

B. balance each other

C. none of the above

D. produce moment of a couple

E. cannot balance each other
37. Center of gravity of a thin hollow cone lies on the axis at a height of ___________________?
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A. none of the above

B. one-half of the total height above base

C. one-fourth of the total height above base

D. three-eighth of the total height above the base

E. one-third of the total height above base
38. A heavy string attached at two ends at same horizontal level and when central dip is very small approaches the following curve ____________________?
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A. hyperbola

B. catenary

C. parabola

D. circular arc

E. elliptical

39. Limiting force of friction is the__________________?
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A. ratio of limiting friction and normal reaction

B. tangent of angle between normal-reaction and the resultant of normal reaction and limiting friction

C. the friction force acting when the body is just about to move

D. the friction force acting when the body is in motion

E. minimum force of friction

40. A pair of smiths tongs is an example of the lever of__________________?
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A. zeioth order

B. second order

C. fourth order

D. third order

E. first order

41. Which of the following is not the unit of power ?
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A. kcal/sec

B. kcal/kg sec

C. hp (horse power)

D. kW (kilowatt)

E. kg m/sec

42. On the ladder resting on the ground and leaning against a smooth vertical wall, the force of friction will be_________________?
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A. upwards at its upper end

B. none of the above

C. perpendicular to the wall at its upper end

D. zero at its upper end

E. downwards at its upper end

43. 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_________________?
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A. density of metal cant be determined

B. none of the above

C. metal is twice as dense as water

D. metal will float in water

E. metal is twice as dense as unknown fluid

44. A force acting on a body may_________________?
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A. balance the other forces acting on it

B. retard its motion

C. change its motion

D. all of the above

E. introduce internal stresses

45. The C.G. of a plane lamina will not be at its geometrical centre in the case of a__________________?
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A. rectangle

B. circle

C. square

D. equilateral triangle

E. right angled triangle
46. If n = number of members andy = number of joints, then for a perfect frame, n =_________________?
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A. 2/ -4

B. 3/-2

C. 2/-3

D. 2j-l

E. j-2

47. 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_______________?
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A. friction

B. limiting friction

C. static friction

D. kinematic friction

E. repose
48. The weight of a body is due to ___________________?
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A. forces experienced by body in atmosphere

B. gravitational force of attraction towards the center of the earth

C. centripetal force of earth

D. gravitational pull exerted by the earth

E. force of attraction experienced by particles

49. If a rigid body is in equilibrium under the action of three forces, then _____________________?
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A. these forces are equal

B. B. and C. above

C. none of the above

D. the lines of action of these forces meet in a point

E. the lines of action of these forces are parallel

50. In actual machines_______________?
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A. mechanical advantage is less than velocity ratio

B. mechanical advantage is unity

C. none of the above

D. mechanical advantage is greater than velocity ratio

E. mechanical advantage is equal to velocity ratio