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

Homework Help: Homework problem on basic motion

  1. Jan 31, 2008 #1
    1. The problem statement, all variables and given/known data

    A person jogs eight complete laps around a 400m track in a total time of 13.5 minutes. Calculate, in m/s the average velocity.

    2. Relevant equations

    3. The attempt at a solution

    I thought that I knew how to do this, but I think I just figured out the average speed. This is what I did:

    400x8= 3200m

    13.5/1 x 60sec./1 min= 810 seconds

    3200m divided by 810 sec.= 3.95 m/sec
  2. jcsd
  3. Jan 31, 2008 #2
    At the end of the eight laps the person is where they started, so the final displacement is 0. Since velocity is defined as displacement divided by time, time is irrelevant, and the average velocity is 0 also.

    You're correct, you've calculated the average speed.
  4. Feb 1, 2008 #3
    Thank you!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook