Question

According to conservation of energy i.e.
Total Energy before =Total Energy after.
So is'nt this theory fails when we lift a book from ground to keep it on top of the table? If yes, how? And if no, how?

Answer 1

no this theory doesn't fail because if we lift book from ground this they have kinetic energy but no potential energy .and at top of table they have potential energy but no kinetic energy . hence it mean energy convert one form to another form. hence energy is always conserv .

Answer 2

yes it is when we
 lift a book the kinetic energy used is lost is stored in form of potential energy due to height