how can you tell if someone is doing work on a box? They are doing work on the box if:

weighs more when they push it
doesnt move backwards when they pull on it
moves forward when pushed
doesnt move forward when its pushed

Question

how can you tell if someone is doing work on a box? They are doing work on the box if:

weighs more when they push it
doesnt move backwards when they pull on it
moves forward when pushed 
doesnt move forward when its pushed

anonymous · Answer

$$W = F \times d \times \cos \theta$$

Work = force* displacement* cos theta, which means if there is no displacement with the amount of force then no work is being done.

So, if the box moves forward when pushed, then there is work being done.