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Homework Help: Average speed without time

  1. Sep 23, 2009 #1
    1. We drive a distance of 1 kilometer at 14 km/h. Then we drive an additional distance of 1 kilometer at 30 km/h. What is our average speed?

    2. average speed= total distance / total time

    3. 22mp/h
  2. jcsd
  3. Sep 23, 2009 #2
    If your velocity is 14km/h, then if you drove a distance of 14km it would take you 1 hour, as I'm sure you're aware. Thus if you only drove a distance of 1 km . . .

    What is the formula for velocity? Think about the dimensions (units) of velocity.
  4. Sep 23, 2009 #3
    the formula for velocity is

    v= distance / time

    and i think the 14 km/h is regarding the speed
  5. Sep 23, 2009 #4
    Yes, you're right. I tend to use velocity as synonymous with speed, which isn't correct. Often it will be negligible, though.


    Just plug and crank, now.
  6. Sep 23, 2009 #5
    but i dont know how to find the time
  7. Sep 23, 2009 #6

    If your speed is 14km/h,
    and you travel a distance of 1 km,
    then the time is ?

    I'm sorry, I'm not sure I can walk you much farther without giving you the answer, but let me know if this doesn't help and I'll think of another way. =)
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