CENTRE OF GRAVITY

CENTRE OF GRAVITY

C.G.: - is the point through which the whole mass of the body acts, irrespective of position of the body.

SHAPE	FIGURE	C.G. ABOUT ‘Y’ AXIS
Uniform rod	Fig.1 | CG of Uniform rod	d/2
Triangle	Fig. 2 | CG of Triangle	h/3
Trapezium	Fig.3 | CG of Trapezium	(2a+b)h/3(a+b)
Semi-circle	Fig.4 | CG of Semi circle	4r/3π
Quarter of a circle	Fig.5 | CG of Quadrant	4r/3π
Semi-ellipse	Fig. 6 | CG of Semi- ellipse	4b/3π
Cylinder	Fig. 7 | CG of Cylinder	h/2
Solid hemisphere	Fig. 8 | CG of Solid hemisphere	3r/8
Solid cone	Fig.9 | CG of Hollow cone	h/4
Hollow cone	Fig. 10 | CG of Solid cone	h/3

• C.G. of an isosceles triangle with base ‘P' and side 'q' is ✓(4p^2- q^2)/6

• C.G. of an equilateral triangle with side 'a' = a/2√3 from any side

• CENTRE OF PERCUSSION :- is the point of application of the resultant of all the forces tending to cause a body to rotate about central axis.

      Centre of percussion of a homogeneous rod of length 'l' , suspended at the top will be= 2l/3

   

       Centre of percussion of a solid cylinder of radius 'r' resting on a horizontal plane will be = 3r/2