Re: [Phys-l] Work and Energy: which first?

[John Denker <jsd@av8n.com>]

Scott Hill wrote:

> How do other people handle this chicken and egg problem?

You can do it either way.  It's a matter of personal preference.

  (As for me, I have a strong preference for energy first, but
   de gustibus non disputandum.)

Here's how I define it:
  http://www.av8n.com/physics/thermo-laws.htm#sec-energy


> I'm thinking about how to teach work and energy to my introductory
> class.  I like the interpretation of work as a mechanical transfer of
> energy, as I think it clears up the sign issues.  

Yes.

> However, I've seen
> energy defined as "the ability to do work", which of course dumps us
> into a circular definition.  

So don't define it that way.  That is a terrrrible definition.

For starters, it's just plain wrong.  It would be wrong even if it
weren't circular.  It is easy to come up with situations that have
more energy but less ability to do work, as discussed at:
  http://www.av8n.com/physics/thermo-laws.htm#sec-energy