
#1
Mar809, 06:50 PM

P: 10

1. The problem statement, all variables and given/known data
(a) If you follow a diet of 2140 food calories per day (2140 kilocalories), what is your average power consumption in watts? (A food or "large" calorie is a unit of energy equal to 4.2*10^3 J; a regular or "small" calorie is equal to 4.2 J.) Note for comparison that the power consumption in a table lamp is typically about 100 watts. ___ watts (b) How many days of a diet of 2140 large calories are equivalent to the gravitational energy change from sea level to the top of Mount Everest, 8848 m above sea level? Assume your weight is 61 kg. (The body is not anywhere near 100% efficient in converting chemical energy into change in altitude. Also note that this is in addition to your basal metabolism.) ____ days 2. Relevant equations Power = F * v Power = W / delta t I know that 1 watt = 1 J/s 3. The attempt at a solution I converted 2140 calories to Joules, which is 2140 * (4.2*10^3) = 8988000 J I'm not sure what I need to do from there because I can't figure out the work. Any help would be appreciated! 



#2
Mar809, 11:04 PM

HW Helper
P: 5,346

What is the definition of a watt?
If you have Joules in a day, and you can figure out how many seconds are in a day ... As to Everest what is the potential energy increase required? m*g*h ? 



#3
Mar809, 11:10 PM

P: 10

I figured it out:)
a) (2140 cals *2400 J) / (24 days * 60 minutes * 60 seconds) b) (61 kg * 8848 m * 9.8 m/s) / (2140 cals *2400 J) 



#4
Mar809, 11:40 PM

HW Helper
P: 5,346

Average power consumption in watts 



#5
Mar809, 11:42 PM

P: 10

Good catch! That was a typo...I meant 4.2 * 10^3 J.
Thanks LowlyPion:) 


Register to reply 
Related Discussions  
PC power consumption  Electrical Engineering  1  
power consumption  General Physics  4  
Computer Power Consumption  Programming & Computer Science  5  
Does the average person run on 96.85 watts?  Classical Physics  16  
Measuring power consumption  Electrical Engineering  10 