Tuesday, 1 March 2016

newtonian mechanics - Climbing Stairs and Calories Burnt


I climb stairs to work (20 floors) every day . The least amount of work my body is doing by gaining potential energy (P.E) = mgh where m is mass , g is acc. due to gravity and h is height . Assuming every floor is 1 metre high . Mass -> 70kg Work Done Comes out to 70*10*20 = 14000J . 1 calorie = 4.2 Joules . So I am burning somewhere around 3000 calories. Right? But this calculation seems way off. I do not feel this tired after climbing 20 floors. What am I missing?




Answer



Due to an accident of history there are two different units called the calorie and the Calorie - yes, the only difference is the capital C.


The calorie is 4.2J but the Calorie is 4.2kJ, and the calories counted in diets are actually Calories even though they are invariably written on the food packaging with a small c.


So you only used 3 Calories walking up the stairs. You'll need to do a lot more walking to lose weight :-)


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