A block of mass 25 kg is raised bu 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

The FBD for the two cases is shown in fig.
In first case, let the force exerted by the man on the floor is `N_(1)`. We have
`N_(1)=T+50g`
Block is to be raised without acceleration, so
`T=25 g`
`:. N_(1)=25 g +50 g =75g = 75 xx 10`
`=750 N`
In second case, let the force exerted by the man on the floor is `N_(2)`. we have `N_(2)=50g-T and T=25g`
`:. N_(2)=50g-25g=25g=25xx10=250N`
As the floor yields to a downward force of 700 N, so the man should adopt the second case.