Newton's laws and levers

[lilblake91]

I'm doing a project for school, and I'm sure this seems elementary to some of you science wizzes, but which one of newton's laws is for levers? I'm sure it's Newton's 2nd law of motion (pretty sure) but is there a law specifically for levers like the law of gravity?

[Turtle]

I'm doing a project for school, and I'm sure this seems elementary to some of you science wizzes, but which one of newton's laws is for levers? I'm sure it's Newton's 2nd law of motion (pretty sure) but is there a law specifically for levers like the law of gravity?

 

Archimedes is attributed with the 'Law of Levers'. Here's a link I found putting 'law of levers' in the search engine:

http://www.uz.ac.zw/science/maths/zimaths/33/archimed.htm

What is your project assignment? Does it mention Newton specifically?:) :umno: :)

[lilblake91]

Archimedes is attributed with the 'Law of Levers'. Here's a link I found putting 'law of levers' in the search engine:

http://www.uz.ac.zw/science/maths/zimaths/33/archimed.htm

What is your project assignment? Does it mention Newton specifically?:) :rolleyes: :)

My project is we have to take a toy, and explain how it uses newton's laws. I chose a Tonka Bulldozer, which has a bunch of levers to resemble the functions of a real bulldozer. I just want to know which of newton's laws this applies to. I can't use Archimedes'.

[Erasmus00]

My project is we have to take a toy, and explain how it uses newton's laws. I chose a Tonka Bulldozer, which has a bunch of levers to resemble the functions of a real bulldozer. I just want to know which of newton's laws this applies to. I can't use Archimedes'.

 

Levers essentially use newton's second law. The only difference is that instead of for translational motions its for rotational motions. The law becomes torque = moment of inertia*angular acceleration.

 

This is the generalization of Archimedes lever principles.

-Will

[Qfwfq]

Actually I'd say all three, perhaps the second is actually just a tad less crucial since you don't really need to reckon acceleration. The third is certainly important, as static equilibrium is central to the analysis.

 

If you want to see exactly how it works, get a copy of the Principia, be prepared to decrypt the way things were said in the late 16 hundreds, and read his demonstration that the three axioms are equivalent to the principles already in use by the mechanics, for designing various contraptions. It comes fairly shortly after the axioms, or laws of motion, but offhand I can't say exactly. For your purposes, you might perhaps prefer the most recent English translation by I.B. Cohen and Anne Whitman, if your school library already has it.

 

In more modern day terms, it's a matter of the two works being equal and of the displacement of each point being proportional to its distance from the fulcrum, therefore inversely proportional to the force.

[Qfwfq]

It is Corollary II