HP formula
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Work = Force x Distance. If you push a 100 pound box 1 foot, you have 100 pound-feet of work.
Power = Work/Time. If it took you one minute to push that 100 pound box one foot then the power you expended was 100 pound feet per minute. If it took you two minutes then you did 50 pound-feet per minute of work. Get it?
From James Watt in the late 1800's - the number he came up with for one HORSEPOWER is 33000 pound-feet per minute or 550 pound-feet per second. So what James Watt figured was that a typical horse could pull or lift 550 pounds one foot in one second.
Power = Work/Time. If it took you one minute to push that 100 pound box one foot then the power you expended was 100 pound feet per minute. If it took you two minutes then you did 50 pound-feet per minute of work. Get it?
From James Watt in the late 1800's - the number he came up with for one HORSEPOWER is 33000 pound-feet per minute or 550 pound-feet per second. So what James Watt figured was that a typical horse could pull or lift 550 pounds one foot in one second.
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"Work = Force x Distance. If you push a 100 pound box 1 foot, you have 100 pound-feet of work."
I think the 100 pound box is LIFTED, not PUSHED. Pushing is too vague since friction would have to be defined.
Steve
I think the 100 pound box is LIFTED, not PUSHED. Pushing is too vague since friction would have to be defined.
Steve
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Originally posted by 10HAAP
"Work = Force x Distance. If you push a 100 pound box 1 foot, you have 100 pound-feet of work."
I think the 100 pound box is LIFTED, not PUSHED. Pushing is too vague since friction would have to be defined.
Steve
"Work = Force x Distance. If you push a 100 pound box 1 foot, you have 100 pound-feet of work."
I think the 100 pound box is LIFTED, not PUSHED. Pushing is too vague since friction would have to be defined.
Steve
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yep-- Hp= (tq*rpm)/5252
This lets us see how you can "make" hp just by revving the engine higher. This makes sense because the engine is moving more air and burngin more fuel at higher rpm, so it SHOULD make more HP.
It also explains why we can multiply torque but not power. Since power is the product of force AND time, we can trade one to get the other with gears. IOW, we can get more force by trading in some time and vice versa with gears. however, the overall product of POWER will remain constant.
That's why it IS hp that rules, not TQ. People mistakenly think that "tq moves the load, hp keeps it moving". Not true. You can't feel a difference between torque and hp. When someone says an engine has "good low end torque", then actually mean that it has good low end HP (which IS tq).
Tq *is*hp, in a sense. Hp is the RATE that torque is applied.
Clear as mud?
Justin
This lets us see how you can "make" hp just by revving the engine higher. This makes sense because the engine is moving more air and burngin more fuel at higher rpm, so it SHOULD make more HP.
It also explains why we can multiply torque but not power. Since power is the product of force AND time, we can trade one to get the other with gears. IOW, we can get more force by trading in some time and vice versa with gears. however, the overall product of POWER will remain constant.
That's why it IS hp that rules, not TQ. People mistakenly think that "tq moves the load, hp keeps it moving". Not true. You can't feel a difference between torque and hp. When someone says an engine has "good low end torque", then actually mean that it has good low end HP (which IS tq).
Tq *is*hp, in a sense. Hp is the RATE that torque is applied.
Clear as mud?
Justin
#10
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Originally posted by DavidTD
In "theory" it is either pushed or lifted as the term is distance. But I see your point.
In "theory" it is either pushed or lifted as the term is distance. But I see your point.
The original W = F x D assumes that the load is lifted - that is, (to oversimplify) F = M. If you lift a 100 lb box 1 foot, you have done 100 ft-lb of work.
Rusty
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