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Homework Help: Newton's Laws of Motion Question

  1. Sep 24, 2006 #1
    okay, so I've tried this problem and I keep getting it wrong. I would really appreciate some help in solving it. Here is the question:

    The parachute on a race car of weight 8820 N opens at the end of a quarter-mile run when the car is traveling at 35 m/s. What total retarding force must be supplied by the parachute to stop the car in a distance of 1000m?

    I know there is probably some really simple equation to solve it but I just can't seem to get it. What i tried was using the equation Vsquared=Vosquared + 2ad

    I got 0=35squared + 2a(1000), a=.6125 and then plugged that into F=ma to get F=900(.6125)=551.25

    I am I even on the right track with this? Please help!
  2. jcsd
  3. Sep 24, 2006 #2


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    Looks fine to me.
  4. Sep 24, 2006 #3
    Thanks for looking. I found out the reason I kept getting it wrong was that I forgot the negative sign. It's the silly mistakes that do you in.
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