Question

A 75.0 kg man pushes on a 500,000 ton wall for 250 s but it does not move. How much work does he do on the wall?

Answer 1

No work

Explanation:

Work is equal to a force times a displacement (parallel to the force)
`W=F*D`
It is energy that causes a mass to be moved.

In this situation the wall does not move, ie zero displacement, therefore he does no work on the wall.

#W=F*D =F*0=0J#

Answer 2

`0J`

Explanation:

Work is defined by the equation

`W=F*d`

`F` is the force in newtons

`d` is the distance in metres

Since the wall didn't move anywhere, that means that he did no work or `0` joules of work.

This can be a trick question because of the time given `(250s)`, but you always have to follow with the definition of work, which is force multiplied by distance. Since the distance is not moved, then no work is done.