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# How much power do you have?

panic15
How much power do you have? (if you don't know the equation google it)

The way i measured mine is how fast I did 10 press ups and then applied it to the eqation. My power is 429 Watts. Post yours.
Gagnar The Unruly
You could also get on a rowing machine and get an actual readout of the amount of watts you are producing, but it takes practice to know how to do it right.
panic15
Well most good gym eqipment do tell you how much power you are producing.
EanofAthenasPrime
 panic15 wrote: How much power do you have? (if you don't know the equation google it) The way i measured mine is how fast I did 10 press ups and then applied it to the eqation. My power is 429 Watts. Post yours.

You have the power of mass*3*10^8! Essentially enough to destroy our entire solar system
panic15
Do I? My science teacher has more power than me :S
Soltair
Lol

Hm... It's a bit strange to calculate power in such a way. I'm sure that there is a proper apparatus to do so, or that there could be one by the way. Also I'd like to know why you just thougth about measuring your power?
Bikerman
 panic15 wrote: How much power do you have? (if you don't know the equation google it) The way i measured mine is how fast I did 10 press ups and then applied it to the eqation. My power is 429 Watts. Post yours.

So tell me, which equation did you use? I presume you used Fd/t? Then there is the question of what measurements you used. How did you calculate the energy expenditure? Simple measuring weight times height of press-up would not do of course, so I'm presuming you used a more complex calculation to allow for this?
Keran
You should have posted a link to this whole equation on checking how much power do you have... I have a hard time finding it, there's lots of crap about power.
panic15
Bikerman wrote:
 panic15 wrote: How much power do you have? (if you don't know the equation google it) The way i measured mine is how fast I did 10 press ups and then applied it to the eqation. My power is 429 Watts. Post yours.

So tell me, which equation did you use? I presume you used Fd/t? Then there is the question of what measurements you used. How did you calculate the energy expenditure? Simple measuring weight times height of press-up would not do of course, so I'm presuming you used a more complex calculation to allow for this?

I measured it in school. So we had to use a simple equation (onl;y studying for gcse's). I can't remember what equation I used (too many going through my head). Of course there was many flaws as there was too many variables such as tiredness heart rate etc.
Bikerman
panic15 wrote:
Bikerman wrote:
 panic15 wrote: How much power do you have? (if you don't know the equation google it) The way i measured mine is how fast I did 10 press ups and then applied it to the eqation. My power is 429 Watts. Post yours.

So tell me, which equation did you use? I presume you used Fd/t? Then there is the question of what measurements you used. How did you calculate the energy expenditure? Simple measuring weight times height of press-up would not do of course, so I'm presuming you used a more complex calculation to allow for this?

I measured it in school. So we had to use a simple equation (onl;y studying for gcse's). I can't remember what equation I used (too many going through my head). Of course there was many flaws as there was too many variables such as tiredness heart rate etc.

If you cannot remember the equation then you must at least remember what data you collected. What did you measure? The time taken for 10 press-ups is one datum. What other data did you measure?
newolder
Bikerman>... What other data did you measure?

Or, we could assume a few (verifiable by confirmation) Gaussians to come up with the required estimate. Within a few kilogrammes or so...

panic15 is probably uk-based, teen-angel. 60 +/- 6 kilogrammes is my first guess.

Is that of the order 667 Newtons force?
Bikerman
 newolder wrote: Bikerman>... What other data did you measure? Or, we could assume a few (verifiable by confirmation) Gaussians to come up with the required estimate. Within a few kilogrammes or so... panic15 is probably uk-based, teen-angel. 60 +/- 6 kilogrammes is my first guess.

Ahh...some sense
Can you elaborate on this a little?
newolder
Bikerman wrote:
 newolder wrote: Bikerman>... What other data did you measure? Or, we could assume a few (verifiable by confirmation) Gaussians to come up with the required estimate. Within a few kilogrammes or so... panic15 is probably uk-based, teen-angel. 60 +/- 6 kilogrammes is my first guess.

Ahh...some sense
Can you elaborate on this a little?

Yep.

Next we need the species:: i'd go for homo sap. to give an estimate through which this weight was moved during a complete cycle of a push-up...

Bikerman
newolder wrote:
Bikerman wrote:
 newolder wrote: Bikerman>... What other data did you measure? Or, we could assume a few (verifiable by confirmation) Gaussians to come up with the required estimate. Within a few kilogrammes or so... panic15 is probably uk-based, teen-angel. 60 +/- 6 kilogrammes is my first guess.

Ahh...some sense
Can you elaborate on this a little?

Yep.

Next we need the species:: i'd go for homo sap. to give an estimate through which this weight was moved during a complete cycle of a push-up...

LOL..sounds reasonable.
OK - so now we get a vector diagram something like this?
dac_nip
ok..the first thing that comes to my mind when I saw the title was the intensity of my "wave". Matter behaving as waves..how much energy does my body contain according to the waves that it produces de broigle..hehe
newolder
From Bikerman's ::

Hence, the work done in a single push-up is the force (60g Newtons) times the distance (in metres) through which it moved. That distance depends upon the position of panic15's centre of mass... Let's guess it's 2/3rds or 67% up from the feet. And, finally, the power (in Watts), or rate of doing work, is the above divided by the time (in seconds) for 1 push-up.

All approximations and measurement errors should be taken into account too to give the uncertainty (error-bar) on the result.
newolder
 dac_nip wrote: ok..the first thing that comes to my mind when I saw the title was the intensity of my "wave". Matter behaving as waves..how much energy does my body contain according to the waves that it produces de broigle..hehe

No need for de Broglie here... Try Einstein: E = mc^2 gives the equivalent energy in a typical guy: E = 5.4 +/- 0.5 petajoules (PJ) with the figures in play.
Bikerman
 newolder wrote: From Bikerman's :: Hence, the work done in a single push-up is the force (60g Newtons) times the distance (in metres) through which it moved. That distance depends upon the position of panic15's centre of mass... Let's guess it's 2/3rds or 67% up from the feet. And, finally, the power (in Watts), or rate of doing work, is the above divided by the time (in seconds) for 1 push-up.
Yep - that was around the figure for Centre of Mass that I was going to use (65% was my estimate). I'll divide the difference and go for 66.

OK...now to do this properly (and what other way should we attempt) we need to firm up some assumptions.

Mass and Height
I'm going to assume Panic15 is between 15 and 17 yrs old based on the information to date (particularly the school references in his postings).
(Note to Ed. It would be useful if we could somehow factor out or cancel the height and mass components in favour of the Body-Mass-Index since I have some good data on BMI but not on the two components, and, more importantly I've got some fairly interesting correlations between arm length and BMI from a couple of studies which could be very useful. I'll look at re-phrasing the math this later on (unless you want to have a look and see if you can simplify-out a way to slot the BMI into the formulae rather than separate Mass and Height figures). I haven't finished defining the problem yet so I'm still collecting variables.
For the moment we'll assume Panic15 is male, and, from reading other posts, a keen computer gamer.
[I was tempted to assume that this would mean a greater 'weighting' on his weight (if you will pardon the pun) since my natural prejudice would be that there is a correlation between computer games and weight. Having checked-up I can report that this unwarranted assumption will not be made, based on a sound statistical survey which shows no such correlation (table2).*]

I will, therefore, assume that Panic is average in weight and height for the median age range chosen - ie 16yrs.
The following is the BMA quoted stats for this age:
Table 1
Boy Age 16 Year
Optimal Height....172cms...........Range (154-194cms)
Optimal Weight...60kg...............Range (40-98kg)

Notes
% of overweight boys in 2000 is given by the Office of Nat Stats at 20.3% with 95% 'confidence boundaries' of 17.90<->22.82. Stats on children (below 19) seem to be based on norm referencing with the 95th percentil defining the acceptible range. Children with a BMI outside the 95th percentile are described as obese (they use the words 'severely overweight').

So this gives us
h = 1.72m (+12.8%, -10.5%)
w = 60kg (+63%, -33%)

Back to the diagram

The next unknown is, then, the distance moved (đ) which cannot be derived from existing data.
One rough and ready method would be to use the length of one arm as roughly the distance (Ó) on the diagram, then simple trigonometry can be used to calculate đ.
Learnardo thought that the total arm-span of a male was equal to the height of the same, and as a rough approximation it works fairly well, but we still have the problem of removing the dimension of the wrist and the subtraction of the width of the torso before we could use this measure.
Starting with 1 unknown (d), and then introducing 2 more variables, simply to arrive at a 'rule of thumb' estimate for the original unknown, does not seem sensible in this instance. Another approach would seem to be indicated. I will think this through a bit more later (I've got some work to do on the new site now

Here is the table showing that computer users are not more porky than the average

Table 2 - Correlations between computer use, mobile phone use and body mass index for 17yr old sample group. Linear regression, adjusted for gender, physical exercise, and parents' education

......................................................Mean BMI, (StdDev).....Beta coefficient..............p-value
............................................................................................(95% boundaries)...................

Computer at home;No...........................21.3 (2.9)
..........................Yes without Internet.....21.6 (3.0)...........0.57 (0.15 to 0.98] .................0.007
..........................Yes with Internet..........21.3 (3.1)...........0.23 (-0.09 to 0.56).................0.16
Weekly computer use (hours)....0........21.1 (3.0)
................................................>1<3......21.2 (2.9)...........0.10 (-0.21 to 0.41).................0.52
................................................>3<6......21.3 (2.9)..........0.12 (-0.20 to 0.44).................0.46
................................................>6<12....21.6 (3.0)..........0.31 (-0.0.38 to 0.65).............0.081
...............................................>12<15...21.7 (3.4)..........0.25 (-0.14 to 0.65).................0.21

Cell phone bill (month-Euro)
....None....21.0 (3.4).........-0.53 (-1.09 to 0.04)................0.068
..................................................<10......21.3 (3.6).........-0.20 (-0.60 to 0.21)................0.34
...............................................>10<20...21.3 (2.9).........-0.25 (-0.49 to -0.006)............0.045
...............................................>20<35...21.4 (2.9)
...............................................>35<85...21.7 (2.9)...........0.29 (-0.04 to 0.63)................0.085
newolder
Bikerman>...The next unknown is, then, the distance moved (đ) which cannot be derived from existing data.

With a little gymnastics, we can make a good guess tho'...

A push-up (wen eye were a lad) moved the centre of mass (chest) through a distance as close as able (and a bit more) to an arm's length (the gymnast is on tip-toes - at worst fitness - with palms down and flat) and return.

Should simplify things...
newolder

I use a mountain bike to cover, on average, 1 lap of Teesdale (Screw Loose to Holwick Head to Middleton in Teesdale to Screw Loose) that is 16.2 +or- 0.3 km long in a period of sadde-time that varies from 3000 to 4200 seconds - weather & other chaos dependent. My current weight is 650 Newtons (~67 kilogrammes times g).

Hence, the work/energy per lap, E=650 x 16 000, ~10^7 Joules and expressed as power (dE/dt=10^7/3.6x10^3), is roughly 3 kilowatts.

Gagnar The Unruly
Newolder,

That would only be the case if you were powering yourself straight upwards for 10 miles. Since your inertia is your friend on most of a bike ride, a lot of the force you need to overcome is friction and wind resistance.

On a 5k run, I'm able to maintain a pace (about 6:15/mi) at which I'm burning about 1250 kcal/hr (about 1.5 kW), although not all of that is in keeping me moving forward. When I erg for a similar amount of time, I expend calories at a remarkably similar rate, but my total output watts are way lower. On a 7:00 2k piece, I'm burning a bit more than 1300 kcal/hr, but only generating 300 W of actual power, on average. The rest of the power I'm exerting must be to keep my metabolism going and heart pumping. The best rowers in the world can, I believe, maintain slightly over 1 hp for the full 5.5 min. it takes them to row a 2k.
newolder
Phew! I just knew that MTB-ing isn't rocket science after all! Maybe after i've got the parachutes working properly i'll risk some of the steeper climbs around here.

So, on my circuit (that starts and ends at the same height above sea-level), it's simply inertia, bearings, ground and air friction that i'm working against - Oh! and the impact from a Weiner/hot-dog that someone thought it amusing to throw at me from an opposite-laned vehicle

I'll never (again) reach the power of the rowers you mention tho' - more like the power of a retired pit-pony than a Shire, in my case. So it goes. ed.
Gagnar The Unruly
What amazes me is how much energy is used up keeping the motor running. I think it's crazy that only about 1/5 of the power I (or anyone else, really) can produce is going towards real physical work. The rest is going straight from hamburger to hot air.
benjmd
I'm curious about why the original poster decided to ask about how much power people have! What does any particular measure of power mean? To the idea of measuring time to complete 10 pushups, I would say that that measure is inaccurate. The only way to really assess "maximal" physical exertion is to basically max out your effort. You can only do pushups so fast, so while two people might be able to do 10 pushups in the same time, one might be able to do 90 more while the other might only be able to do 30 more. Personally I like the "You have the power of mass*3*10^8! Essentially enough to destroy our entire solar system" comment!
newolder
 benjmd wrote: ...Personally I like the "You have the power of mass*3*10^8! Essentially enough to destroy our entire solar system" comment!

Likable but false.

The 6x10^17, or so, Joules of energy, equivalent to the mass of a typical guy or 65 +or- 5 kilogrammes, released by Einstein's most-remembered, is a seriously small anthropic mist. ed.

The 2-million year recent history of the Carina nebula is on a much grander scale than anything humans have achieved hitherto. There's time yet (but not greater than 10 thousand years) before eta pops again...

_AVG_
According to an experiment in which I ran up some stairs and measured their height, along with recording the time, I have:
632.4 Watts of Power!!