# Very hard

1. Dec 12, 2004

### Rapta3

In a certain library the first shelf is 12.0 cm off the ground, the remaining 4 shelves are each spaced 33.0 cm above the previous one. If the average book has a mass of 1.90 kg with a height of 22.0 cm, and average shelf holds 29 books (standing vertically), how much work is required to fill this book shelf from scratch, assuming the books are all laying flat on the floor to start?

2. Dec 12, 2004

### Physicsisfun2005

The change in potential energy is equal to the Work $$W=Ug$$........just add them up for each row :rofl: :rofl: :rofl:

3. Dec 12, 2004

### HallsofIvy

Staff Emeritus
"Very hard"???

You consider multiplying integers "very hard"?

The work to put each book on a shelf is the weight of the book times the height it is lifted to the shelf.