View Single Post
Old 08-08-2012, 04:19 PM   #83
d1ck
Senior Member
 
Join Date: Jul 2012
Drives: Black 2013 FRS
Location: Newfoundland
Posts: 249
Thanks: 31
Thanked 83 Times in 54 Posts
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
I'm sorry coheed but you're wrong. horsepower is simply a unit of measurement of power just like watts. (1 horsepower = 746 watts). Power is measured by using work / time, or (force x distance) / time. The amount of work to accelerate a mass on earth is proportional to the following:
object mass & change in velocity
Object mass & change in height relative to gravity
Spring rate & change in spring length (only for when you're compressing a spring)
Non conservative losses (due to friction) (and radiation I think)
There's also some for heat if I remember correctly


Just to demonstrate why you're wrong lets do a simple calculation with your theory:
Your theory: 550 lb-m @ 1 ft/s = 1 HP
lets use the FRS travelling at 60 mi/h on a flat road and see how much HP that would require

(2900/550) x (88 fps) = 464 HP

Wow! That's a lot of horsepower just to travel at 60 mi/h!

Quote:
Take that 550lb weight and lift it 2ft/sec and you get 2hp, and so on. On an inertial dyno you take a fixed weight, and accelerate it. Using the drum weight and friction of the roller assembly, you can calibrate it to measure hp quite easily.
I apologize that I missed this in your most recent post, and that is in fact correct. The unit of HP was created with this in mind, however, it's still just simple newtonian physics at play here and not as complicated as you previously suggested.

Last edited by d1ck; 08-08-2012 at 04:38 PM.
d1ck is offline