Alexander, who weighs 159lbs , decides to climb Mt. Krumpett, which is 5460ft high. For his food supply, he decides to take nutrition bars. The label on the bars states that each 100g bar contains 10g of fat, 40g of protein, and 50g of carbohydrates.Alexander wants to know exactly how many bars to pack in his backpack for the journey. To provide a margin of safety, he assumes that he will need as much energy for the return trip as for the uphill climb. How many bars should Alexander pack?

Question

How would I even go about solving this problem? The total calories is 450 for a total bar that I calculated, is this right?

Answer 1

yes, 450 Food calories is correct.

I am reluctant to work this out, as the problem is ridiculous. It wants you to assume 100 percent efficiency in conversion of candy to gravational potential energy ...which is a most riciculous assumption...then assume there is no gain of energy (loss of PE) going back down the mountain. All this makes the problem border on science fiction. Also, I wonder if whomever created this problem is competent in science.

All that notwithstanding...

numbercandybars*450FoodCalories*2000calories/FoodCalorie*4.18joules/cal
is the energy from the candy bar.

The change in gravitaional potential energy going up the mountain is mass*g*change in height.

set those equal, and you can solve for the number of candy bars given the silly assumptions above.

Answer 2

I am getting 22.6, but it says that is the wrong answer.

450*2000*4.18=3762000

159*5460*9.8=8507772
I am setting them equal to eachother and getting 2.26, but it says the answer is wrong. Please help.