1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: What's this problem talking about?

  1. Nov 26, 2006 #1
    I've come across a problem and I have no idea on how to solve it.. I know it involves converting units but how do you convert kcal/h into J/gal??? Please take your time to help me get started. Thanks!

    Here is the problem:
    For saving energy, bicycling and walking are far more efficient means of transportation than is travel by automobile. For example, when riding at 10 mi/h, a cyclist uses food energy at a rate of about 400kcal/h above what he would use if merely sitting still. (In exercise physiology, power is often measured in kcal/h rather than in watts. Here 1 kcal=1 nutritionist's Calorie = 4,186 J) Walking at 3mi/h requires about 220 kcal/h. It is interesting to compare these values with the nergy consumption required for travel by car. Gasoline yields about 1.30 x 10^8 J/gal. Find the fuel economy in equivalent miles per gallon for a pesron a) walking, and b) bycicling.
  2. jcsd
  3. Nov 26, 2006 #2
    It's all right there in the problem. Just read it a bit more carefully, starting with the fuel economy for walking.
  4. Nov 26, 2006 #3
    Yeah I figured it out. I just kept converting and converting lol until I ended up with mi/gal. k thanks
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook