# Homework Help: Work done

1. Apr 1, 2006

### Geographer

Hi all, would someone tell me how to calculate work done? We did this ages ago in school, but I can't seem to remember how to do it. There was also other things, but all I can remember is something like force x mass divided by something... sorry. If anyone has the faintest clue what I mean then please help!

You must excuse my lack of knowledge of physics, but I assume this forum is for people of all levels.

2. Apr 1, 2006

### Pengwuino

Work done can be calculated in a number of ways. In general it can be written as:

$$W_{total} = W_{conservative} + W_{non - conservative}$$

This one is basically for when you have more then 1 force acting on a system where certain forces can be considered conservative (gravity for example) and certain forces can be considered non-conservative (friction for example).

$$W = F*\Delta x$$

This is if you have a constant force acting on something for a certain distance. For example, say you have a force of 10N acting upon a block for 10m, you use that to say that 100 J of work have been done on the block.

$$- W = \Delta K + \Delta P$$

This is for when you change something’s potential energy along with its kinetic energy. For example, if you are pushing a block up a hill and you know its initial kinetic and potential energy along with its final kinetic and potential energy, you can determine the work done on the block.

3. Apr 1, 2006

### Geographer

Thanks for your answer, Pengwuino; that has cleared it up for me.

Not exactly a physics question, but I hope someone can point me in the right direction: does anyone know of any active chemisty and geography forums (especially the latter). Most I've come across seem to be defunct with little activity; it's a shame they aren't all like this one!