Ok, so I'm supposed to run up some stairs and then calculate how much effect (watts) I used.(adsbygoogle = window.adsbygoogle || []).push({});

This is how I did it:

Stairs was 2.52 meters high and 3.5 meters long, my mass is 72 kilos and I ran up the stairs in 2.72 seconds.

Energy for moving up 2.52 meters:

[tex]E_{p} = mgh = 72*9.82*2.52 = 1781.7408[/tex]

[tex]P_{1} = \frac{E_{p}}{t} = \frac{(\frac{72*9.82*2.52}{2.72})}{2.72} \approx 0.66 kW[/tex]

Energy: for moving the 3.5 meters horizontally:

[tex]v = \frac{3.5}{2.72}[/tex]

[tex]E_{k} = \frac{mv^2}{2} = \frac{72(\frac{3.5}{2.72})^2}{2.72}[/tex]

[tex]P_{2} = \frac{E_{k}}{t} \approx 0.22 kW[/tex]

Alltogether: [tex]P_{1} + P_{2} = 0.66 + 0.22 = \underline{0.88 kW}[/tex]

I'm not supposed to think about air friction etc.

Question is ofcourse: Am I anywhere close to answering this in a correct way?

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# Homework Help: Running up some stairs, kiloWatts

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