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

As we know that work done is defined as product of force and displacement in the direction of applied force

so we can say it is

or we can say

so we will have following options

A)Pushing against a locked door

There is no work done in above case as there will be no displacement in that case so work done is ZERO

B) Carrying a box down a corridor

While we move done and carrying a box then work done by gravity on the box while our work done is negative work.

C) Pulling a trailer up a hill

In above case our work done to pull a box up a hill is positive work as we need to work against gravity

D)  Suspending a heavy weight with a strong chain

During suspension there is no displacement so there will be no work done in above case

so correct answer will be

Pulling a trailer up a hill

measuring things 1 litre of water

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide