Question

who works up the ladder? what is he doing? who is yelling?
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Answer 1

➡️ 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.

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