A. h/2
B. J/3
C. h/6
D. h/4
✅ The correct answer is option D.
Strength of Materials MCQs
72. 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____________________?
A. remain horizontal
B. slant up towards direction of pull
C. slant down towards direction of pull
D. unpredictable
✅ The correct answer is option C.
73. On the ladder resting on the ground and leaning against a smooth vertical wall, the force of friction will be__________________?
A. downwards at its upper end
B. upwards at its upper end
C. perpendicular to the wall at its upper end
D. zero at its upper end
✅ The correct answer is option D.
74. Pick up the incorrect statement from the following _______________?
A. The C.G. of a circle is at its center
B. The C.G. of a triangle is at the intersection of its medians
C. The C.G. of a rectangle is at the inter-section of its diagonals
D. The C.G. of a semicircle is at a distance of r/2 from the center
✅ The correct answer is option D.
75. The coefficient of friction depends on_________________?
A. area of contact
B. shape of surfaces
C. strength of surfaces
D. nature of surface
✅ The correct answer is option D.
76. In the equation of virtual work, following force is neglected_______________?
A. reaction of any smooth surface with which the body is in contact
B. reaction of a rough surface of a body which rolls on it without slipping
C. reaction at a point or an axis, fixed in space, around which a body is con-strained to turn
D. all of the above
✅ The correct answer is option D.
77. If rain is falling in the opposite direction of the movement of a pedestrain, he has to hold his umbrella_________________?
A. more inclined when moving
B. less inclined when moving
C. more inclined when standing
D. less inclined when standing
✅ The correct answer is option D.
78. 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. B. and C. above
✅ The correct answer is option D.
79. The centre of percussion of a solid cylinder of radius r resting on a horizontal plane will be______________?
A. r/2
B. 2r/3
C. r/A
D. 3r/2
✅ The correct answer is option D.
80. Which of the following is the example of lever of first order________________?
A. arm of man
B. pair of scissors
C. pair of clinical tongs
D. all of the above
✅ The correct answer is option D.