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Homework Help: Simple average speed/average velocity problem

  1. Mar 3, 2010 #1
    1. The problem statement, all variables and given/known data
    Jeremy is training for a boxing match. He runs due north at an average speed of 16km/h for the first 8.0 km and returns to the training camp at an average speed of 10 km/h. Calculate his average speed and his velocity.


    2. Relevant equations
    Vavg = Total Distance / Total Time
    Average Velocity = Final displacement / Total time taken


    3. The attempt at a solution
    16 km/h for first 8.0 km = 0.5 hours
    10 km/h for the trip back = 0.8 hours
    Total time taken = 1.3 hours
    Total distance = 16 km

    Average speed = 16/1.3
    =12.3 km/h.

    The answer on my sheet is 12km/h. Am I doing something wrong or is it just rounded?
    For average velocity, would it be 0? Since there is no displacement from the starting point?

    I am just starting physics, and I just need guidance in the right direction.

    Thank you.
     
  2. jcsd
  3. Mar 3, 2010 #2

    Delphi51

    User Avatar
    Homework Helper

    Your calcs look good. Yes, the answer should be rounded to 2 digits since all the given quantities are accurate to 2 digits.
     
  4. Mar 3, 2010 #3
    Alright, thank you!
    Sorry if this seems like a silly question, I just want to make sure my work is correct before going forward.
     
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