#2. If a book weight .5 kg, there are 20 books on a shelf and 100 shelves in the bookstore, how much potential energy is there in the bookstore (in terms of the above potential energy of the books on shelves)? Assume that the acceleration due to gravity is 10 m/s^2 and that the shelves are all 1 m high. 1 joule = 1 kg x 1m/s^2 x 1m
Potential energy of each book = m.g.h= 5 x 10 x 1 joule= 50 joulesP.E of 20 books= 20 x 50 = 1000 joules( one shelf )P.E of books in 100 shelves = 100 x 1000= 1,00,000 joules.