Question

how to verify the law of conservation of energy with example of simple pendulum and an object thrown upward

Answer 1

do u have S chand srearch there

Answer 2

when the Bob is at rest , it initially has kinetic energy. When it moves to the extreme position A it aquires potential energy and while returning to the position A it again gains kinetic energy and hence the energy remains conserved . the same process happens when the Bob moves to the extreme position C.
in this complete process energy is neither gained nor lost but it remained conserved.