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Homework Help: Exerted force?

  1. Dec 14, 2009 #1
    A 950 kg car starts from rest and reaches a velocity of 50.0 km/h in 8.50 s. If the driver has a mass of 75.0 kg, what force is exerted on the car and driver during this time interval?

    I am very confused on this question. I was thinking:

    50.0/3.6 =13.88 +8.5 = 22.38s

    1025/22.38 .... but obviously all of that is wrong seeing as how it doesn't give me any of answers I can choose from :( help! what am i doing wrong
  2. jcsd
  3. Dec 14, 2009 #2


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    Gold Member

    the mass of the car and driver is 1025 kg, OK
    please watch your units, 13.88 m/s is the velocity of the car after 8.5 seconds, then its acceleration is v/t, not v + t, and
    Where does this this formula come from? Please write out your relevant equations.
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