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: Why is it difficult to start a car in winter?

  1. Feb 10, 2008 #1
    1. The problem statement, all variables and given/known data
    [ Urgent: I have to give a physics practical exam cum viva voce tomorrow for class +2 ]
    I don't have any idea as to which topic in physics it is related to. I just know that in winter, you pull the choke to allow more gasoline into the engine, which starts the engine right away. But I need a simple answer based on a principle in physics.

    Mr V
  2. jcsd
  3. Feb 10, 2008 #2
    Liquids evaporate less when cold. Gasoline becomes thicker. And finally, what happens when a battery becomes cold in regards to the chemical process? It happens _____ than usual.
  4. Feb 10, 2008 #3
    Yeah, what PowerIso said. And also that lubricant oils become less viscous at cold temperatures. An electrical engine block heater designed to offset this problem is usually placed on the oil pan.
  5. Feb 10, 2008 #4
    I think the problem with starting your car in winter has more to do with the characteristics of your battery and the internal energy of it. Not to mention the CCA rating
  6. Feb 11, 2008 #5
    Thanks to all of you. I found out the answer I needed while surfing the net. They are more or less what you told me.
    The basic reason, apart from thickening of the oil, is that internal resistance of battery is more at low temperature, which means less current, which means difficulty in starting the car.

    Thanks again.

    Mr V
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook