From: J. Forster (jfor@quik.com)
Date: Sun Sep 22 2002 - 20:07:45 PDT
GOTAM35 wrote:
'My understanding of physics may not be the best, but the energy required to
move the mass of the trucks at a given speed should be the same for the same
amount of weight. '
No. See my previous post but one. First off, it's power (which is energy/unit
time) not energy
Energy is joules, ergs, watt-hours, horsepower-hours, foot-pounds, BTUs,
calories, etc. If you do work on something, like pumping water uphill or raising
a weight, that increases it's (potential) energy. A pound of diesel oil has
about 22,000 BTU's. That's its (stored potential) energy content.
Power is watts, ergs/second, horsepower, foot-pounds/second, BTUs /hour,
calories/hour, etc. It is the rate at which energy is produced or used. If you
lift a 550# weight vertically up at 1 foot per second, that's 550 ft-lbs/second
(equals 1 HP)
***************************
Corrected:
If you converted 1 lb/second of diesel with 100% efficiency into work, the
power would be equal to 56 HP. (not 40)
The correct conversion is: 1 BTU/sec is approx 1.39 HP (This is gotten from the
following: 1 BTU/sec = 1.05 KW and 1 HP is about 746 Watts, therefore 1 BTU/sec
= 1.05 / 0.746 = 1.39 HP)
That's what happens when I watch Jamed Bond while doing email.
Sorry.
-J
******************************
OK so far?
Power is (torque) x (rotation speed) An engine putting out 550 ft-lbs at 60
RPM is putting out 1 HP, as is an engine putting out 55 ft-lbs at 600 RPM or 5.5
ft-lbs at 6000 RPM. None of this is not engine specific, but basic physics.
-John
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