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