Aamc 6 bs 118

[letaps]

Hey,

Can anyone explain why C is the right answer?

If both Steve and Joe performed the same work tasks, which of the following statements would describe their individual energy consumption?
A) Steve’s body would consume more energy because of his lesser weight.

B) Steve’s body would consume less energy because of the greater basal metabolic rate in younger people.

C) Joe’s body would consume more energy because of his greater weight.

All other things being equal, if Joe had to carry around twice the weight that Steve carried and do the kinds of tasks firefighters do such as climbing ladders and stairs, Joe would have to expend more energy than Steve. Option C is the correct answer. Option A comes to the opposite conclusion, so it is incorrect. Options B and D suggest basal metabolism might be involved, but the question involves expenditure of energy in performing external work, not on energy involved in maintaining the body at rest, so options B and D are irrelevant.

D) Joe’s body would consume the same amount of energy as Steve’s because the basal metabolic rates are equal.

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[afarooq2]

Someone please correct me if my logic is off, but the way I would approach this question is through elimination. Like the answer summary states, the BMR is the energy level the body needs to function when it's completely at rest, basically to carry out functions of the vital organs, which does eliminate B and D. When you have them expending energy, the BMR doesn't really apply. I don't know the physiology behind it, but from choosing between A and C, C makes more sense logically. Someone of heavier weight has more to carry, say up a ladder or something similar.

Just my two cents, anyone know the science behind it?

 

[Meat]

Work = Force x Displacement (remember that the unit for work is joules, meaning energy!)

Assuming displacements are equal, the energy that both the bodies consume during the same displacement is dependent on force:

F=ma

W=ma x D or The energy required to perform a task = (mass of performer)(acceleration due to gravity)(distance over which the action is performed)

The overall mass of the heavier man is greater, meaning that the work done should be more.

This is how I interpreted it.

 

[wooki]

i just ran into this question too and i don't quite get it.

i understand that people with more mass will have to expend more energy to do the same amount of work.

but taking into consideration BMR...
1. do larger people have higher bmr than smaller people?
2. assuming yes, why is it said that skinnier people have higher metabolism?

 

[Akarat]

i just ran into this question too and i don't quite get it.

i understand that people with more mass will have to expend more energy to do the same amount of work.

but taking into consideration BMR...
1. do larger people have higher bmr than smaller people?
2. assuming yes, why is it said that skinnier people have higher metabolism?

First off, basal metabolic rate has a lot of factors that go into it when determining how many calories an individual person burns. That being said, if you picture two people with an equal percentage of skeletal muscle, bone, fat, etc., the one that weighs more will have a higher BMR. This is because in terms of absolute mass, the heavier person has more cells, which means more ATP is required in terms of absolute numbers. The amount of ATP required for each cell is the same, though because of the initial assumption that the two people have an equal percentage of tissues.

Skinner people don't necessarily have a higher metabolism than fatter people. As stated before, there's a lot of variables when it comes to individual BMRs. For instance, a muscular person of the same weight as an average person will have a higher BMR because skeletal muscle tissue is more metabolically active. Age also plays a big role as well. Teenagers have a relatively higher BMR than adults because teenagers are still growing and require energy not only for the maintenance of their bodies, but also for additional growth.