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Physics Problem involving Kinematics

  1. Sep 20, 2007 #1
    1) A typical car's brakes can create a maximum acceleration of less than 5 m/s2 . How
    close can you get to a stop sign before you start braking?

    I don't think it's even doable, since there's no initial velocity. Or am I wrong?
     
  2. jcsd
  3. Sep 20, 2007 #2

    olgranpappy

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    you are correct, sir. though, you could write the answer in terms of the unknown v_0.
     
  4. Sep 20, 2007 #3
    Oh. So then my answer would be in variables, and not actual numbers?
     
  5. Sep 20, 2007 #4

    olgranpappy

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    yep. you can write the answer for the shortest braking distance in terms of the initial velocity and the acceleration... you might be able to guess it (up to a factor of 1/2) from dimensional analysis (i.e., looking at the units).
     
  6. Sep 20, 2007 #5
    So can I use V^2 = Vo^2 + 2ax as the formula for solving this?
     
  7. Sep 20, 2007 #6

    olgranpappy

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    yeah, since you know what v has to be when the car has stopped. you can solve for x in terms of v0 and a.
     
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