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Homework Help: Kinematics question help please ?

  1. Sep 5, 2010 #1
    kinematics question help please :)?

    So I've tried to attempt this problem by finding possible things like time or velocity but it just does not come out right. Help is greatly appreciated :)


    At the instant the traffic light turns green, an automobile starts with a constant acceleration a of 2.0 m/s^2. At the same instant a truck is 13.4 m down the road and traveling with a constant speed of 9.3 m/s. (a) How far beyond the traffic signal will the automobile overtake the truck? (b) How fast will the automobile be traveling at that instant?

    heres some work I did:
    t= 1.44 s

    Thanks :)
    Last edited: Sep 5, 2010
  2. jcsd
  3. Sep 5, 2010 #2
    Re: kinematics question help please :)?

    If you know how far are the truck and the car from the traffic light at any moment, this problem is easy to solve.

    So, for the car you have


    And for the truck


    Now you just need to figure what is [itex]x_0[/itex] and what is the condition for the car and the truck to meet.
  4. Sep 5, 2010 #3
    Re: kinematics question help please :)?

    What is x(t)?
  5. Sep 5, 2010 #4
    Re: kinematics question help please :)?

    [itex]x(t)[/itex] is the function with [itex]t[/itex] as a variable. It tells you what is the distance [itex]x[/itex] from the traffic light at the time [itex]t[/itex].
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