Question

how can we find cemtere of gravity of irregular plane lamina pls answer important

Answer 1

Let A be an irregular lamina in the below figure, for which the position of center of gravity is to be determined. Mark three fine holes at a, b and c, near the edge of lamina. Now suspend the given lamina along with a plumb line from the hole a, using a pin(or a nail) clamped horizontally on a retort stand. Check that the lamina is free to oscillate on the nail about the point of suspension. When lamina has come to rest, draw a straight line ad along the plumb line.
Repeat the procedure by suspending the lamina through the hole b and then through the hole c for which we get straight lined be ad, be and cf intersect each other at common point G which is the position of center of gravity of lamina.