1. Not finding help here? Sign up for a free 30min 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!

Finding acceleration from a position vs. time

  1. Oct 5, 2015 #1
    1. The problem statement, all variables and given/known data
    Given the following graph of displacement vs time for an object moving in a straight line (assume const accel):
    Find the acceleration between t=0 and t=4

    2. Relevant equations
    A= ((vi-vf)/2)/time

    3. The attempt at a solution
    I've tried find the area of t=0 to t=4 in order to convert to velocity and then to acceleration. However, the problem is I don't know how to find the area because the graph is curved. I tried getting the area above the line and subtracting it from the total area of t=0 to t=4. This didn't work because I can't find the area of the hypothetical circle of which the area above the line would be a fraction of. Thanks

    P.S. I know there are other questions that ask the same thing but they are either irrelevant to my particular question or went unanswered
     

    Attached Files:

  2. jcsd
  3. Oct 5, 2015 #2
    Since you are given displacement vs. time, the derivative at a point will give you the velocity. Taking a derivative of the velocity graph gives you the acceleration.

    Since the displacement graph is roughly quadratic on [0, 4] the second derivative will be a constant.

    Thus you can find the instantaneous velocity at any two points, take their difference, and divide by time to get the acceleration.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted