A block of mass 25 kg is raised by a 50kg man in two different ways as shown in fig. what is the action on the floor by the man in the two cases? If the floor yields to a normal force of `700N`, which mode should the man adopt to lift the block without the floor yielding?

Explanation

Mass of the block, m=25kg, mass of the man, M=50kg.
Force applied to lift the block` F=mg=25xx9.8=245N`
Weight of the man, `Mg=50xx9.8=490N`
Fig.(a) When the blokc is raised by the man by applying force F in upward direction, reaction equal and oppostie to F will act on the floor in addition to the weight of the man.
`therefore` Action on the floor `Mg+f=490+245=735N`
Fig. (b) When the blokc is raised by the mass applying force F over the rope (passed over the pulley) in downward direction, reaction equal and opposite to F will act on the floor.
`therefore` Action on the floor Mg-F=490-245=245N
Floor yields to a normal force of `700N`, the mode (b) should be adopted by the man to lift block.