# Re: Repeal of the National Speed Limit Law

```in article <95187.072906MICHAEL@MAINE.MAINE.EDU>
Michael Johnson <MICHAEL@MAINE.MAINE.EDU> wrote:

>In article <3ten51\$3d4@curly.cc.emory.edu>, lparker@curly.cc.emory.edu (Lloyd R.
>Parker) says:
>>
>>Sorry, but an object in motion possesses an amount of KE equal to 1/2
>>times its mass times its velocity squared.  Basic physics.  To take the
>>object from 10 mph to 0 mph requires removing a certain amount of KE
>>equal to 1/2 times the mass times 100 (1/2m10^2 - 1/2m0^2).  To take the
>>object from 20 mph to 10 mph requires removing KE equal to 1/2 times the
>>mass times 300 (1/2m20^2 - 1/2m10^2).
>>
>>The amount of force you have to use is not a constant -- it will depend
>>upon how much KE you have to remove.

>Hmm.. we really need to do something about these lloyderers.

Lloyd is right is this case.

>Care to
>cite your reference Lloyd? Unfortunately, I don't have a physics text
>here, but in this case that hardly matters.

Uhhh, you probably should have checked with your physics text.

>Allow me to reiterate. When attempting to make calculations in
>physics (and chemistry) it is important to remember that if the units
>don't come out right, you've made a mistake or some invalid assumptions.

>   W = F * D                                                      (1)

>Work is force times distance. Pretty basic comic book physics.

So far, so good.

>   E = W / T                                                      (2)

>Energy is work over time. Again, basic comic book physics.

Nope, *power* is work per time.  Energy is work.  Two different names
for the same thing.  With this wrong equation, there's no point in

Well, I'll just make one more point...
> ... Hm.. there's your velocity squared. But wait a second, how did that
> extra time value get in there?