How much Work Does Gravity do?
A 1.1 kg book is lying on a 0.74 m-high table. You pick it up and place it on a bookshelf 2.2 m above the floor.
How much work does gravity do on the book?
height 1 (h1): .74 m
height 2 (h2): 2.2m
Height difference: 2.2 – .74= 1.46
displacement x force:
mass x gravity x height
1.1kg*9.8*1.46 = 17.6 J
Since gravity is forcing down, it would be negative!
2) How much work does your hand do on the book?
Same answer as the previous question but a positive force.