# A Unit Question: Flicking a Switch

1. Dec 14, 2008

### thepopasmurf

If I wanted to work out the calculations for flicking a lightswitch, what units am I dealing with when I am determining how hard it is to flick the switch?

For example, I am sure that I wouldn't say it takes a certain amount of force because a large force over a short amount of time wouldn't do much. Is it impulse, or work?

2. Dec 14, 2008

### mgb_phys

It depends what you want to measure.
There is a peak force needed to overcome the switch mechanism
You apply this force for a certain time so their is an impulse, you also have to do a certain amount of work on the spring holding the switch. Finally when the switch moves over into the new position it has a certain momentum.

3. Dec 14, 2008

### thepopasmurf

Well, the problem I have in mind is flicking a light switch with a projectile. I want to know what velocity I have to give an object of mass M in order to flick a light switch. Of course different switches vary and I'm not sure what I should call this varying quantity and what unit it is

4. Dec 14, 2008

### Cspeed

You could measure the lightest object needed to push down the light switch, using only gravity. F= MA and you know the force. As far as velocity, you would need to know the impulse.