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[angebot]

Today was a beautiful morning after my night shift. It is about 20C outside and sunny. I decided to walk home which is about 8.5 Km (really 8.4875 Km) from my work at a brisk 4.8 Km per hour taking almost exactly 1 hour 45 minutes carry a backpack that is easily 10 Kg stuffed with laptop, clothes and other things on my back. Counting the inertia of

Comments

[dichroic]

Sure. 62 kg + 10 kg = 72 kg - this is mass. Force = mass * gravitational acceleration: 72 kg * 9.8 m/s^2 = 705.6 newtons. Work = force * distance. In one hour you go 3218 meters: 705.6 newtons * 3218 meters = 2270620 joules. Convert units: 1 joule = 0.000238845896627496 calories, and energy is the capacity to do work. So you have the capacity to burn 2270620 * 0.000238 = 5404 calories in that hour. Bear in mind when people talk about weightloss and calories they usually mean kilocalories. If my math is right (it probably isn't, I don't have my engineering books here to properly check units and conversions) you burn 5.4 kilocalories.

[angebot]

Wow thanks!

[dichroic]

I should note that that only accounts for the work to get you from one place to the other, in pure physics terms. It doesn't account for any of your metabolic processes, breathing, heart beating, or anything like that. Also that 5.4 (food) calories is for one hour - I just used the speed you provided. Multiply by 1.75 to get nearly 9.5 cal for the whole hour and 45 minutes. Sorry it's not a more impressive answer ;-)

[maffewk]

Technically that's not true. While you do exert 705.6 N on the ground due to the acceleration of gravity, you're not accelerating yourself 9.8 m/s2. When you walk you are intermittently pushing on the the ground that that is the force you are exerting. Your body has to use energy to exert that force but at the same time your metabolic processes are expending energy as well. Not to mention the fact that you have to take the grade of the surface into account.

Your best bet is to use one of the many estimator calculators that are out there.

This one seems to be a good one:
http://www.drgily.com/activity-calories-burned.php?ex_id=11820