Question

A girl picks a 0.57 kg book up off the floor and places it on a bookshelf 1 meter above the floor. The book now has 5.6 J of potential energy, how much work did the girl do?

Answer 1

Answer:

Work done to pull the book upwards is 5.6 J

Explanation:

As we know be the relation of work and potential energy that change in gravitational potential energy of the system is equal to the work done on it

so we will have

$W = U_f - U_i$

when book is placed on the ground then its initial potential energy is given as

$U_i = 0$

final position potential energy is given as

$U_f = 5.6 J$

now we have

$W = 5.6 - 0$

$W = 5.6 J$