Comments on: What fraction of a 300-Calorie pizza slice must you eat to supply that energy. PLEASE HELP. http://design4kitchen.com/2009/04/27/what-fraction-of-a-300-calorie-pizza-slice-must-you-eat-to-supply-that-energy-please-help/ New design ideas for your kitchen Tue, 22 May 2012 00:45:17 +0000 http://wordpress.org/?v=2.5 By: O-360 http://design4kitchen.com/2009/04/27/what-fraction-of-a-300-calorie-pizza-slice-must-you-eat-to-supply-that-energy-please-help/#comment-2018 O-360 Tue, 30 Nov 1999 00:00:00 +0000 http://answers.yahoo.com/question/?qid=20090426180440AAP8Tzf#comment-2018 a. The normal force is 400 lbs, or (400/2.2)*9.8 = 1782N. The friction force is μN = 1782*0.3 = 534N. The work done is W = F*d = 534*5 = 2,673J. b. If the efficiency is 25%, you need to generate 4 times as much energy to delivery the necessary work. Wt = 2,673/0.25 = 10,691J c. Food “calories” are actually Kilo-Calories (Kcal), and 1Kcal = 4186 Joules. So, the 300 calorie slice of pizza is actually 300*4186 or 1.256*10^6 joules. It would take: slice fraction = 10,691/1.256*10^6 = .0085 slice a. The normal force is 400 lbs, or (400/2.2)*9.8 = 1782N. The friction force is μN = 1782*0.3 = 534N. The work done is W = F*d = 534*5 = 2,673J.

b. If the efficiency is 25%, you need to generate 4 times as much energy to delivery the necessary work.

Wt = 2,673/0.25 = 10,691J

c. Food “calories” are actually Kilo-Calories (Kcal), and 1Kcal = 4186 Joules. So, the 300 calorie slice of pizza is actually 300*4186 or 1.256*10^6 joules. It would take:

slice fraction = 10,691/1.256*10^6 = .0085 slice

]]> By: Tupher http://design4kitchen.com/2009/04/27/what-fraction-of-a-300-calorie-pizza-slice-must-you-eat-to-supply-that-energy-please-help/#comment-2019 Tupher Tue, 30 Nov 1999 00:00:00 +0000 http://answers.yahoo.com/question/?qid=20090426180440AAP8Tzf#comment-2019 haha physics 131 umass. i don’t think you take into account the normal force because the box is only moving in the x direction. instead work equals only friction force i believe haha physics 131 umass. i don’t think you take into account the normal force because the box is only moving in the x direction. instead work equals only friction force i believe

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