Powering the Human Brain: How Long Can One Snickers Bar Last?

[tennischick89]

1. The human brain consumes about 22 W of power under normal conditions, though more power may be required during exams. How long can one Snickers bar (280 cal per bar) power the normally functioning brain? [Note: The nutritional calorie, 1 cal, is equivalent to 1000 calories (1000 cal) as defined in physics. In addition, the conversion factor between calories and joules is as follows: 1 cal = 1000 calories = 1 kcal = 4186 J]


2. I know I need to use P=W/t



3. I converted cal. in the snickers bar to kcal and then did .280 kcal/4186 to get joules in one snickers. plugged that in for W but I'm not getting the right answer

 

[tiny-tim]

welcome to pf!

hi tennischick89! welcome to pf!

1 cal = 1000 calories = 1 kcal = 4186 J]
…
3. I converted cal. in the snickers bar to kcal and then did .280 kcal/4186 to get joules in one snickers. plugged that in for W but I'm not getting the right answer

you divided by 4186?

eat more snickers bars! ​

 

[tennischick89]

Ha oh my goodness...thanks!