Engineering Mechanics

61. The C.G. of a plane lamina will not be at its geometrical centre in the case of a

1. right angled triangle
2. equilateral triangle
3. square
4. circle
5. rectangle.

View answer

62. The C.G. of a right circular solid cone of height h lies at the following distance from the base

1. h/2
2. J/3
3. h/6
4. h/4
5. 3/i/5.

View answer

63. The C.G. of a solid hemisphere lies on the central radius 3r

1. at distance — from the plane base 3r
2. at distance — from the plane base 3r
3. at distance — from the plane base 3r
4. at distance — from the plane base or
5. at distance — from the plane base.

View answer

64. The center of gravity of a triangle lies at the point of

1. concurrence of the medians
2. intersection of its altitudes
3. intersection of bisector of angles
4. intersection of diagonals
5. all of the above.

View answer

65. The center of gravity of a uniform lamina lies at

1. the center of heavy portion
2. the bottom surface
3. the mid point of its axis
4. all of the above
5. none of the above.

View answer

66. The center of percussion of a solid cylinder of radius r resting on a horizontal plane will be

1. r/2
2. 2r/3
3. r/A
4. 3r/2
5. 3r/A.

View answer

67. The center of percussion of the homogeneous rod of length L suspended at the top will be

1. L/2
2. L/3
3. 3L/4
4. 2L/3
5. 3L/8.

View answer

68. The coefficient of friction depends on

1. area of contact
2. shape of surfaces
3. strength of surfaces
4. nature of surface
5. all of the above.

View answer

69. The co-efficient of friction depends upon

1. nature of surfaces
2. area of contact
3. shape of the surfaces
4. ail of the above.
5. (a) and (b) above.

View answer

70. The effort required to lift a load W on a screw jack with helix angle a and angle of friction <j) is equal to

1. Wtan(a + <)>)
2. Wtan(a-<)>)
3. Wcos(a + <t>)
4. Wsin(a + <(>)
5. W (sin a + cos <j>).

View answer