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

Here , mass of block , ` m = 25 kg`
Mass of man , `M = 50 kg`
Force applied to lift the block
`F = mg = 25 xx 9.8 = 245 N`
Weight of man `W =Mg = 50 xx 9.8 = 490 N`
(a) When block is raised by man as shown in force is applied by the man in the upward direction This increase the apparent weight of the man . Hence action on the Floor
`W = W + F = 490 + 245 = 735 N`
(b) When block is raised by man as shown in Force is applied by the man in the downward direction This decreases the apparent weight of the man Hence action on the floor in this case would be
`W = W - F = 490 - 245 = 245 N`