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

Explanation

Mass of block m= 25 kg
mass of person m= 50 kg
`F -= mg `
` 250 N`
Weight of person w = mg
` = 5xx 10`
`500 N` as shown in figure (a ) force is applied in upward direction due to its apparent weight increase hence force applied by person on block
F = W
`250 + 500`
case 2 :
As shown in figure ( b) when force is applied in downward direction apparent weight decrease
Hence force applied by person on the block
mg = F
`=500 - 250`
Force acting on the surface is 700 N in case (a ) force acting on surface is more than 700 N and in case (b ) is less than 700 N Hence case ( b) should be used to lift block