1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

What was the car's velocity at t=0?

  1. Sep 20, 2009 #1
    1. The problem statement, all variables and given/known data
    A car accelerates at 1.75 m/s2 along a straight road. It passes two marks that are 30.3 m apart at times t=3.80 s and t=5.15 s. What was the car's velocity at t=0?

    2. Relevant equations

    3. The attempt at a solution
    Im actually not quite sure how to approach this question. Is there some way that i can find the velocity at the beginning of the time interval that is given?
  2. jcsd
  3. Sep 20, 2009 #2
    Re: Velocity

    What is the average speed over the interval from 3.8s to 5.15 s?

    exactly when does the car have this average speed?
  4. Sep 20, 2009 #3
    Re: Velocity

    the average velocity over that time interval is 22.4 m/s. but im not sure what you mean by:
  5. Sep 21, 2009 #4
    Re: Velocity

    if the car goes has speed [itex] v_i [/itex] at the start of the interval and [itex] v_f [/itex] at
    the end of the interval, its average speed is [itex] (v_i + v_f)/2 [/itex]. The speed at _______
    is also [itex] (v_i + v_f)/2 [/itex]. (with constant acceleration)
  6. Sep 21, 2009 #5
    Re: Velocity

    so the middle of the interval (4.48s) would also have the velocity of 22.4 m/s ??
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook