ইঞ্জিনিয়ারিং মেকানিক্স MCQ
41. Center of percussion is-
the point of CG
the point of metacentre
the point of application of the resultant of all the forces tending to cause a body to rotate about a certain axis
point of suspension
42. The centre of a semi-circle lies at a distance of ... from its base measured along the vertical radius.
3π/8
4r/3π
38π/3
3r/4π
43. Kern of a circular section is a concentric circular area having a diameter equal to -
half of the diameter of the section.
One-third of the diameter of the section.
One-fourth of the diameter of the section.
One-fifth of the diameter of the section.
44. The center of gravity of a triangle lies at the point of-
concurrence of the medians
intersection of its altitudes
intersection of bisector of angles
intersection of diagonals
45. Center of gravity of a thin hollow cone lies on the axis at a height of-
one-fourth of the total height above base
one-third of the total height above base
one-half of the total height above base
three-eighth of the total height above the base
46. The center of percussion of the homogeneous rod of length L. suspended at the top will be-
L/2
L/3
3L/4
2L/3
47. A solid cone has a height 'h', height of the CG of the cone above the base is-
h/4
2h/4
3h/4
4h/3
48. If rain is falling in the opposite direction of the movement of a pedestrain, he has to hold his umbrella-
more inclined when movirig
less inclined when moving
more inclined when standing
less inclined when standing
49. A projectile is fired at an angle 9 to the vertical. Its horizontal range will be maximum when 9 is-
0°
30°
45°
60°
50. Which of the following is a vector quantity?
Energy
mass
momentum
angle
51. Center of gravity of a solid cone lies on the axis at the height-
one-fourth of the total height above base
one-third of the total height above base
one-half of the total height above base
three-eighth of the total height above the base
52. To parallel sides of a trapezium are a and b its heights is h so CG from base is at.......
π x (a+b)/3h
h/3 .b+2a/b+a
3/8.b+a/a-2h
2h/3. b+2a/b+a
53. A heavy string attached at two ends at same horizontal level and when central dip is very small approaches the following curve-
Catenary
Parabola
Hyperbola,
Elliptical
54. The moment of inertia of a square of side K about an axis through its centre of gravity is-
a² /8
a² /12
a^4 /12
a² /16
55. If a suspended body is struck at the center of percussion, then the pressure on die axis passing through the point of suspension will be-
maximum
minimum
zero
infinity
56. From a circular plate of diameter 6 cm is cut out a circle whose diameter is a radius of the plate. Find the c.g. of the remainder from the center of circular plate-
Area of Circle = πR²
Where R = radius of the circle
D = 2R
D = Diameter of circle
Given
The Diameter of the circular plate = 6 cm
The diameter of the circle to be cut = 3 cm
Radius of circular plate R = 6/2 = 3
Radius of circle r= 3/2 = 1.5
The Center gravity of the circle acts on the center of a circle.
r/R= 1.5/3 = 0.5 cm
0.5cm
1.0cm
1.5cm
2.5cm
57. Pick up the incorrect statement from the following-
The CG of a circle is at its center
The CG of a triangle is at the intersection of its medians
The CG of a rectangle is at the inter-rection of its diagonals
The CG of a semicircle is at a distance of r/2 from the center
58. An irregular body may have more than one center of gravity.
agree
disagree
59. Moment of inertia about the base of a triangle of base 'B' and height '' is-
1/24 bh^4
1/18 bh^3
1/12 bh^3
1/6 bh^3
60. The point through which the whole weight of the body acts is known as--
moment of inertia
center of gravity
center of percussion
center of mass