Question

In which of the following cases is work being done on an object? Question 2 options: Pushing against a locked door Carrying a box down a corridor Pulling a trailer up a hill Suspending a heavy weight with a strong chain???

Answer 1

The answer would be:

Pulling a trailer up a hill

Here is why:

In physics, work is computed by the formula:

W = Fd or F(cosΘ)d

Where: F = Force applied on the object

            d =displacement

So in order for work to be done, the object needs to be displaced. In the case of the trailer, the trailer is being pulled and it is travelling in the direction of the force applied.

The other options the object is not displaced. Even if you exert a force, if the displacement remains the same, then it will always be zero, so the force times displacement will be 0, hence no work is done.