# Math Help - Work done .

1. ## Work done .

The formula of work done is dW=fds cos theta

Why can't it be W=fs cos theta without the d ?

I know the 'd' means change in something .

So does it mean that the change in work done is the force multiplied by the change in displacement cos theta ?

How can a force act on a changing displacement ?

I know my question sounds weird .

Thanks for your help and explaination .

2. Originally Posted by thereddevils

How can a force act on a changing displacement ?
When you lift something, you are in constant touch with that thing...sine there is displacement due to your force(maintained through the contact),,,the force does work(implied by the formula).

However, if you drop something, then the contact is soon lost and no displacement occurs while the thing was in contact with you...which implies no work.