posted by Anonymous .
Eight books, each 8.5 cm thick with mass 1.3 kg, lie flat on a table.How much work is required to stack them one on top of another?
The average height before is 4.25cm
The average height after is 4*8.25cm
work=7(1.3)*(4*.0825 - .0425)*9.8 joules
work = massmoved*change height*g
Make certain you know why seven masses are in the calculation.