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Homework Help: Heat and Kinetic Energy Question

  1. Apr 19, 2009 #1
    1. The problem statement, all variables and given/known data
    Two cars collide as both are traveling at 90km/hr. What is the increase in temperature of the wrecks, assuming that the cars have c = 447 joules/kelvin.

    2. Relevant equations
    Q= mc(change in T)

    3. The attempt at a solution
    I found the joules of kinetic energy equal to 625 joules * mass of car (25 m/s speed = 625/2 joules of KE per car X two cars).
    I then divided that by 447 for the c value, to get 1.4 K. But the answer is not correct?
  2. jcsd
  3. Apr 19, 2009 #2


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    Homework Helper

    Half of that would be correct though wouldn't it?

    Don't you have to consider the total heat into the total mass?
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