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Homework Help: Calculating forward force?

  1. Feb 15, 2016 #1
    1. The problem statement, all variables and given/known data
    Car tires have a coefficient of friction of .06 and the tires are accelerating at 5/ms^2. If the total mass of the car is 500 kgm, calculate the forward force exerted by the car engine.

    2. Relevant equations
    I know that .06 is Mu and Mu is equal to friction/normal force. And I know that force=m*a.

    3. The attempt at a solution
    I sometimes get confused with the difference forces. I calculated the forward force to be 2500 N by doing f=(500)(5). But I'm not sure if that's right because isn't this equation only for normal force? Can it also be for forward force?
    Then I did .06=friction/2500 and I got 150 N for friction. So if friction is 150 N and forward force is 2500 then the net forward force exerted by the car engine would be 2350 N.

    Is this correct? I have a feeling it's not...
  2. jcsd
  3. Feb 15, 2016 #2

    Simon Bridge

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    Science Advisor
    Homework Helper

    Friction between road and tyres is the only force accelerating the car.
    The car engine can push the wheels on the road only as hard as the static friction between tyres and the road allows - any more and the wheels will spin.
    You are being asked to work out this maximum amount of force before the wheels spin.
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