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: Average Speed.

  1. May 10, 2010 #1
    Hey,
    This is kinda a thick question but never mind.
    A car travells 30KM and that for 30mins.
    What is the average speed of the car?


    Formula is Average speed= Distance Travelled DIVIDED BY Time taken.

    But its not 30 DIVIDED by 30 is it?
    Is it 30 DIVIDED by 0.5 as 30mins is half of an hour?
    And how exactly do you work out say 14mins of 1hour?
    (I have the Circle with 3 commas [o,,,] on my calculator, forgot what its called sorry but I dont quiet get how it works.)
    Thank you!!
     
  2. jcsd
  3. May 10, 2010 #2

    Doc Al

    User Avatar

    Staff: Mentor

    That depends on the units you wanted. 30 km/30 minutes = 1 km/min
    That's fine. That will give you km/hour as your units of speed.
    How many minutes in an hour? Set up a fraction.
     
  4. May 10, 2010 #3
    Your average speed is DeltaX/Deltat if you want your speed in km/hour you can convert your units using dimensional analysis. (km/min) * (60min/hour)
     
  5. May 10, 2010 #4
    Thanks Doc. Understood that.
    And thanks Melgibson for the answer even though I am sorry to say I understood nothing of what you said. But still thank you for the effort.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook