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

Physics: 1d Motion-Instantaneous Velocity vs Average.

  1. Sep 18, 2012 #1
    Trying to create a table with time and instantaneous velocity. (the tables- http://i.imgur.com/8DZsu.png ) How do I go from using the Average Velocity to the Instantaneous Velocity?

    Instantaneous Velocity is the V_avg at t_1 + (delta-t)/2 how do I use this with my data.
    Last edited: Sep 18, 2012
  2. jcsd
  3. Sep 18, 2012 #2


    User Avatar
    Science Advisor

    You have to make some assumptions about the smoothness of the data, because you lose some information from only having sampled data. See if you can fit the data to a particular model function. If you can't, then you can just estimate the instantaneous velocity = the average velocity at the center of each averaging period. The centers of your averaging periods are between each sample point. If you want the instantaneous velocity at your sample points, then you can take the midpoint between each pair of average velocities. Of course, it's all very approximate.
  4. Sep 18, 2012 #3
    So between t1=.05 and t2=.10 you take the mid point of the average velocities which is 30 + 35 = 65/2 = 32.5cm/s? Thus at t2 instantaneous velocity = 32.5cm/s?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook