Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Find initial velocity with accelration as a funt. of t

  1. May 28, 2010 #1
    1. The problem statement, all variables and given/known data

    The acceleration of a particle is given by a_{x}(t)= - 1.94 m/s2 +( 3.05 m/s3 )t.

    Find the initial velocity v_{0x} such that the particle will have the same x-coordinate at time t= 4.00 s as it had at t=0.

    2. Relevant equations

    vx= v0x + the integral ax dt

    3. The attempt at a solution

    What I did was set velocity to 0 moved initial velocity over then integrated acceleration to give me this:

    -v0x= (-1.94 m/s2)t + ((3.05 m/s3)t2)/2

    I then plugged in t=4 and t=0 into the equation which gave me 16.64 -wrong

    I feel Im close, I just dont know how else to approach this problem.
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. May 28, 2010 #2


    User Avatar
    Homework Helper
    Gold Member

    Hello mnafetsc,

    Welcome to Physics Forums!

    I'll give you a hint. You need to integrate twice. Ask yourself this. If you know what a(t) is, how do get an expression for x(t)? After you know that, then consider that the problem statement tells your that x(4 sec) = x0. :wink: You should be able to take it from there.
    Last edited: May 28, 2010
  4. May 28, 2010 #3
    Perfect, integrated twice set x to 0 gives me -4.25 m/s

    Thanks a bunch
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook