Two small pegs (A and B) are at horizontal and vertical separation b and h respectively. A small block of mass M is suspended with the help of two light strings passing over A and B as shown in fig. The two string are always kept at right angles (i.e., `lt APB = 90^(@))`. Find the minimum possible gravitation potential energy of the mass assuming the reference level at location of peg A. [Hint: the potential energy is minimum when the block is at its lowest position]

Answer

`U_(min) = - (1)/(2)Mg [sqrt(h^(2)+b^(2))-h]`