# Smallest possible force

1. Oct 19, 2006

### 123aaa

I have a lab for physics that I have to demonstrate the smallest possible force. The force has to be mearsured by multiplying the mass of the designated object by acceleration. It has to have a continuous and positive acceleration. The distance is that it must travel at least 30 cm. Any ideas and help would be great :).

I had an idea using the air track with a paper clip but it would be kinda typical for our class since everyone is doing it since no one knows what to do.

Thanks.

2. Oct 19, 2006

### Danger

Rats! I was going to suggest a gnat fart until I read further into your post. I don't think that 30cm is achievable with that.

Seriously, I don't understand the question. The smallest possible force wouldn't move anything any appreciable distance. Do you mean the smallest force that will move a designated mass 30cm?

3. Oct 19, 2006

### 123aaa

oh haha, sorry for the unclear question.
Yeah, that's what I meant--moving a designated mass of 30cm.

4. Oct 19, 2006

### Danger

Well,then... F=ma. How long are you allowed to accelerate the given mass? Plug that figure into the formula along with whatever that given mass is.

5. Oct 19, 2006

### way2lazy2care

I'm a little confused too... are u supposed to get it as close to 30 cm as possible?

6. Oct 19, 2006

### 123aaa

It should go to at least 30 cm and it should accelerate for about a maximum of 30 mins.

7. Oct 19, 2006

### Danger

Okay, then... just follow the formula. Use your maximum allotted time to minimize the required force.

8. Oct 19, 2006

### 123aaa

but how am i going to demonstrate the force?

9. Oct 19, 2006

### Danger

Unless I missed something (which is quite possible because I'm on my 8th beer), you didn't mention what the mass is of the body in question. And even when you do divulge it, you're going to have to work it out yourself. I don't know what you mean by 'demonstrate'. That could indicate either a mathematical proof of your conclusions, or a physical staging.

10. Oct 19, 2006

### 123aaa

It's suppose to be a physical staging...and the mass can be any object.

I was thinking of using a paper clip to accelerate with an air track but any better ideas?

11. Oct 19, 2006

### way2lazy2care

well... as for displaying how it works, wouldn't the objet moving be evidence of the force?

as for figuring out force, u need it to be traveling 1cm/min idealy on average
make a graph of distance over time, that being 30cm over 30 mins, take the dirivative(sp?) to get speed(remember u have to start with a speed of 0), then the dirivative(sp?) of that to get acceleration, then figure out the force from that...

12. Oct 19, 2006

### Ki Man

if you are getting really lazy with it, you could always take a small piece of paper and practice blowing it across a table with a dropper =/

a lighter object might be harder to control though so dont go too light