Power

[louie]

How many horsepower is available from 3,000 pounds 7 feet in the air?

[J.C.MacSwell]

How many horsepower is available from 3,000 pounds 7 feet in the air?

 

Sounds like potential energy.

 

Power is rate of work or energy.

[louie]

how much energy is their in 3000lb's 7 ft in the air. can someone figure out how much energy their is in the same weight dropping 6in. per hour.

[J.C.MacSwell]

how much energy is their in 3000lb's 7 ft in the air. can someone figure out how much energy their is in the same weight dropping 6in. per hour.

 

1) 21,000 ft lb of energy

 

2) 1500 ft lb/hr

[louie]

would that be constant for the entire hour

[Marqq]

How many horsepower is available from 3,000 pounds 7 feet in the air?

OK, so 1 hp = 550 foot pounds per second (when referring to mechanical horsepower), which means that 1 hp can lift a 500 lb load 1 foot every second. Perhaps you wanted to know how many watts or joules are available from this system (assuming power transfer is 1:1)?

By the way, 1 hp is about 746 Joules/sec, or Watts. So for this system, I'd assume 1 second of movement and say:

[math]1hp = \frac{550 lb \times 1 ft}{1 sec}; 3000 lbs \times 7 ft = 21000 ft-lbs; 21000 \div 550 = 38.\overline{18} hp[/math]

 

how much energy is their in 3000lb's 7 ft in the air. can someone figure out how much energy their is in the same weight dropping 6in. per hour.

Here we go, now I get that you're asking how much horsepower is being expressed. Half a foot in an hour?? Lets do this, then...

[math] 1 hour = 3600 sec ; 6 in = 0.5 ft

\frac{\frac{3000}{550} \times 0.5}{3600} = 7.\overline{57}\times 10^{-4} hp[/math]

Kinda lame, so I figure you might just be looking for how much potential energy (joules) is available in the system. So, multiply hp of the original 1-second calculation (38.18...) by 746, and you get 28483.64 joules.

 

Edited because I accidentally hit the 'Post' button instead of the preview button before I was finished. This is my first post using the LaTeX math notation system...thanks for the opportunity to try it out.

Edited July 18, 2011 by Marqq

[Airbrush]

How many horsepower is available from 3,000 pounds 7 feet in the air?

 

As Marqq stated above, summarized, 3,000 pounds at 7 feet is 21,000 foot/pounds. Horse Power is 550 foot/pounds/second. If the weight takes one second to reach the ground, you will have about 38 horse power available, or 28,484 watts.

Edited July 19, 2011 by Airbrush

[J.C.MacSwell]

As Marqq stated above, summarized, 3,000 pounds at 7 feet is 21,000 foot/pounds. Horse Power is 550 foot/pounds/second. If the weight takes one second to reach the ground, you will have about 38 horse power available, or 28,484 watts.

 

Keep in mind the kinetic energy of the 3,000 lb weight at the end of the second. It is not an insignificant part of the energy in this case.