Eight bricks 6 cm thick with mass 1.5kg lie flat on a table.how much work is required to top them one on another?

Answer 1

W (for the second brick) = m•g•0.06
W (for the third brick) = m•g•0.12.
W (for the 4th) = m•g•0.18. ....
.................

W(total)=m•g•(0.06+0.12+0.18+ 0.24+0.30+0.36+0.42) =
= 1.68•m•g =1.68•1.5•9.8 =24.7 J