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Focused topic practice

strength of materials MCQs

Practise focused strength of materials questions with marked answers for exam preparation and subject revision.

strength of materials Mcqs
1. 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. Wtana

B. Wan(a-)

C. W

D. W sin (a + $)

E. Wtan(a +
2. Coulomb friction is the friction between_________________?
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A. bodies having relative motion

B. solids and liquids

C. electrically charged particles

D. two lubricated surfaces

E. two dry surfaces

3. Which is the correct statement about law of polygon of forces ?
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A. if any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon taken in order, then the forces are in equilibrium

B. if a polygon representing forces acting at a point is closed then forces are in equilibrium

C. none of the above

D. if any number of forces acting at a point can be represented by the sides

E. a polygon taken in order, then the forces are in equilibrium

F. if any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon, then the forces are in equilibrium

4. The co-efficient of friction depends upon________________?
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A. shape of the surfaces

B. nature of surfaces

C. ail of the above.

D. A. and B. above

E. area of contact

5. The algebraic sum of moments of the forces forming couple about any point in their plane is________________?
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A. equal to the moment of the couple

B. constant

C. both of above are correct

D. both of above are wrong

E. none of the above

6. D Alemberts principle is used for___________________?
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A. determining stresses in the truss

B. solving kinematic problems

C. stability of floating bodies

D. designing safe structures

E. reducing the problem of kinetics to equivalent statics problem
7. The product of either force of couple with the arm of the couple is called________________?
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A. resultant couple

B. moment of the couple

C. resulting couple

D. none of the above

E. moment of the forces

8. If a rigid body is in equilibrium under the action of three forces, then_______________?
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A. B. and C. above

B. none of the above

C. these forces are equal

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

E. the lines of action of these forces are parallel

9. The coefficient of friction depends on_________________?
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A. area of contact

B. all of the above

C. shape of surfaces

D. nature of surface

E. strength of surfaces

10. The algebraic sum of the resolved parts of a number of forces in a given direction is equal to the resolved part of their resultant in the same direction. This is as per the principle of__________________?
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A. independence of forces

B. forces

C. balance of force

D. resolution of forces

E. dependence of forces

11. The C.G. of a plane lamina will not be at its geometrical centre in the case of a______________?
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A. right angled triangle

B. square

C. rectangle

D. circle

E. equilateral triangle

12. The ratio of limiting friction and normal reaction is known as_______________?
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A. angle of friction

B. coefficient of friction

C. sliding friction

D. friction resistance

E. angle of repose

13. Frictional force encountered after commencement of motion is called________________?
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A. limiting friction

B. frictional resistance

C. post friction

D. dynamic friction

E. kinematic friction

14. The unit of force in S.I. units is_________________?
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A. joule

B. kilogram

C. newton

D. dyne

E. watt

15. The maximum frictional force which comes into play when a body just begins to slide over another surface is called_____________________?
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A. limiting friction

B. kinematic friction

C. dynamic friction

D. sliding friction

E. rolling friction

16. The center of percussion of the homogeneous rod of length L suspended at the top will be__________________?
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A. 2L/3

B. 3L/4

C. L/3

D. L/2

E. 3L/8

17. 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. W (sin a + cos )

E. Wtan(a + )
18. A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if______________?
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A. the floor is smooth, the wall is rough

B. the floor is rough, the wall is smooth

C. the floor and wall both are smooth surfaces

D. the floor and wall both are rough sur-faces

E. will be in equilibrium under all condi-tions

19. Pick up wrong statement about friction force for dry surfaces. Friction force is________________?
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A. proportional to velocity of sliding

B. none of the above is wrong statement

C. proportional to normal load between the surfaces

D. independent of the area of contact surfaces

E. dependent on the materials of contact surface

20. The units of moment of inertia of mass are_____________________?
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A. m2/kg

B. kg/m

C. kg/m2

D. kg m2

E. m4

21. Which of the following is not the unit of pressure ?
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A. atmosphere

B. kg/cm

C. ata

D. newton

E. mm of wcl

22. 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. 100

B. 50

C. 500

D. 250

E. 25

23. 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. downwards at its upper end

B. zero at its upper end

C. upwards at its upper end

D. perpendicular to the wall at its upper end

E. none of the above

24. 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

25. A particle inside a hollow sphere of radius r, having coefficient of friction -rr can rest upto height of__________________?
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A. r/A

B. 0.134 r

C. 3r/8

D. r/2

E. r/%

26. The unit of work or energy in S.I. units is________________?
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A. joule

B. newton

C. pascal

D. kilogram meter

E. watt

27. When trying to turn a key into a lock, following is applied___________________?
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A. non-coplanar forces

B. moment

C. lever

D. coplanar force

E. couple
28. The resultant of the following three couples 20 kg force, 0.5 m arm, $ ve sense 30 kg force, 1 m arm, ve sense 40 kg force, 0.25 m arm, + ve sense having arm of 0.5 m will be_________________?
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A. 10 kg, + ve sense

B. 20 kg, ve sense

C. 45 kg, + ve sense

D. 20 kg, + ve sense

E. 10 kg, ve sense

29. 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. double

B. half

C. four times

D. one fourth

E. same

30. A force is completely defined when we specify________________?
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A. none of the above

B. direction

C. all of the above

D. magnitude

E. point of application

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

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

E. if three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two

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

32. Which of the following is not a vector quantity_______________?
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A. acceleration

B. force

C. moment

D. velocity

E. weight
33. Which of the following is not the unit of distance ?
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A. light year

B. millimeter

C. micron

D. angstrom

E. milestone
34. The magnitude of two forces, which when acting at right angle produce resultant force of VlOkg and when acting at 60 produce resultant of Vl3 kg. These forces are____________________?
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A. 3 and 1 kg

B. 2 and 5

C. none of the above

D. V5andV5

E. 2 and V6

35. In detennining 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___________________?
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A. four members with unknown forces of the frame

B. three members with known forces of the frame

C. four members with two known forces

D. two members with unknown forces of the frame

E. three members with unknown forces of the frame
36. 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 down towards direction of pull

B. slant up towards direction of pull

C. none of the above

D. remain horizontal

E. unpredictable

37. Center of gravity of a solid cone lies on the axis at the height_______________?
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A. one-half of the total height above base

B. none of the above

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

D. one-third of the total height above base

E. one-fourth of the total height above base
38. Center of gravity of a thin hollow cone lies on the axis at a height of________________?
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A. one-third of the total height above base

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

C. none of the above

D. one-fourth of the total height above base

E. one-half of the total height above base

39. 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. catenary

B. circular arc

C. elliptical

D. parabola

E. hyperbola

40. In the equation of virtual work, following force is neglected_______________?
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A. reaction at a point or an axis, fixed in space, around which a body is con-strained to turn

B. all of the above

C. reaction of a rough surface of a body which rolls on it without slipping

D. reaction of any smooth surface with which the body is in contact

E. none of the above

41. Forces are called coplanar when all of them acting on body lie in________________?
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A. different planes

B. different points

C. perpendicular planes

D. one point

E. one plane
42. Kinetic friction is the________________?
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A. the friction force acting when the body is in motion

B. ratio of limiting friction and normal reaction

C. dynamic friction

D. tangent of angle between normal reac-tion and the resultant of normal reac-tion and the limiting friction

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

43. The centre of percussion of a solid cylinder of radius r resting on a horizontal plane will be______________?
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A. r/2

B. 3r/A

C. 3r/2

D. r/A

E. 2r/3

44. In actual machines______________?
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A. none of the above

B. mechanical advantage is greater than velocity ratio

C. mechanical advantage is less than velocity ratio

D. mechanical advantage is unity

E. mechanical advantage is equal to velocity ratio

45. A trolley wire weighs 1.2 kg per meter length. The ends of the wire are attached to two poles 20 meters apart. If the horizontal tension is 1500 kg find the dip in the middle of the span________________?
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A. 2.0 cm

B. 4.0 cm

C. 2.5 cm

D. 3.0 cm

E. 5.0 cm

46. A single force and a couple acting in the same plane upon a rigid body________________?
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A. cannot balance each other

B. are equivalent

C. balance each other

D. none of the above

E. produce moment of a couple

47. The center of gravity of a triangle lies at the point of__________________?
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A. intersection of its altitudes

B. all of the above

C. intersection of diagonals

D. intersection of bisector of angles

E. concurrence of the medians
48. The center of gravity of a uniform lamina lies at_______________?
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A. the center of heavy portion

B. the bottom surface

C. all of the above

D. the mid point of its axis

E. none of the above

49. Forces are called concurrent when their lines of action meet in_______________?
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A. different planes

B. two points

C. perpendicular planes

D. one point

E. plane

50. Which of the following is not the unit of work, energy and heat ?
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A. kcal

B. kWhr

C. hp

D. kg m

E. hp hr