I was unable to find posiotn of center of mass of various objects.please teach me the easiest way in finding COM.

the easiest way in finding COM is usually to apply parallel axis theorem and perpendicular axis theorem appropriately. moreover, sometimes calculus is also useful in solving com ques. i would highly recommend ‘physics galaxy’ by ashish arora volume if you want to practice questions, as there are both solved and unsolved problems in there.