Question

a man with box on his head is climbed up a ladder .
the work done by the man on the box is ?
a)positive
b)negative
c)zero
d)undefined

Answer 1

positive

The man carries the box up above to a higher altitude.  The potential energy of the box increases.  This increase in energy comes from the work done by the man.  Hence the work done is positive.

The displacement of the box is in the direction of force exerted by the man on the box  - upwards.  Hence, the product of the force and displacement is positive.  Hence the work is positive.

Answer 2

The man with box moves in order of increasing altitude.Hence there is increase in energy and thus the work done is positive.