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Linear Motion Problem. Help!

  1. Oct 25, 2009 #1
    OK This is a multi step problem that I really do not understand. Here it is:

    Carefree Carnie is driving her parents automobile on an autumn day. While driving with the cruise control set at 50 miles per hour, she notices a construction project's road block in her lane 60 meters ahead. If it takes Carnie 0.45 seconds to react to the sign before she hits the brake to deactivate the cruise control, and the acceleration associated with the braking force is a constant -5.5m/s squared, answer the following questions:

    a) How fast is Carnie traveling in units of meters per second?
    b) How far does Carnie car travel before she reacts and hits the brake?
    c) Once she hits the brakes, how far does she skid, (distance traveled while braking only) before she stopped?
    d) What total distance did carnie travel before she stopped (from the moment she saw the road block to the point at which she stopped?)
    e)Did she hit the roadblock? Explain.

    Any help on this problem would be awesome! Thank you!






    Now I know that this needs an 'attempted' solution but i have no idea where to start! Help me!
     
  2. jcsd
  3. Oct 25, 2009 #2

    Delphi51

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    I have this great method for converting units that I'll share with you.
    Say you have a speed of 20 feet per minute and you want to convert it to meters per second. You just write 20 ft/min and then replace the "ft" with 0.3048 meters and the "min" with 60 s. It looks like this:
    20 ft/min = 20*0.3048 m/60s = 0.10 m/s
    Try that with your miles per hour!
     
  4. Oct 25, 2009 #3
    Thank you Delphi, that helps me with a. Now that I think about it, i know how to do that. I am just really overwhelmed with this problem, i dunno why.
     
  5. Oct 25, 2009 #4

    Delphi51

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    One step at a time! Part b is just a motion at constant speed.
     
  6. Oct 25, 2009 #5
    Ok. I can do that
     
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