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Measuring the average speed of an object

  1. Oct 17, 2009 #1
    Hi everyone,

    http://img372.imageshack.us/img372/6093/img009h.jpg [Broken]

    With the above, I really have no idea other than the standard s=d/t formula, but I doubt that has anything to do with it for a question worth 3 marks, and then looking at the two questions below, it'd make no sense.

    The other idea I had was finding the total time, then the area under the graph for d, giving you s=d/t again, but using the method I just described. Then 25c would be answered by saying that finding instantaneous speed required a tangent drawn to the point etc, as opposed to the whole area under the curve.

    Is the idea of finding d and t using area under the graph right, or am I way off?

    Thanks for the help in advance.
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Oct 18, 2009 #2
    Bump. :)
     
  4. Oct 18, 2009 #3
    dude look a) Vm=X-X0/T-T0=deltaX/deltaT so this is for the avarage speed .
     
  5. Oct 18, 2009 #4
    I've never heard of this formula before, so it's something which we haven't covered in class yet. Hence - it can't be right.
     
  6. Oct 18, 2009 #5
    ah i now , now it is about the uinits i wrote them in my lenguage but this formula is for the avarage speed but i dont now how to writte them in english sorry but it is the formula for avarage speed
     
  7. Oct 18, 2009 #6
    and another thing the avarage speed u can discribe it like this if a car moves with a speed of 3 km/h at the start and 5 km/h at the end u cant put together 5 + 3 and get 8km/h then divide it by 2. 8:2=4km/h so the avarage speed now is 4 km/h so even if the car dosent achive to have this speed but it is simpel to tell that the car can end the road at this speed sorry for my english i now it is bad but it is my 4 lenguage and i am learning it now since 4 months but i see i get better
     
  8. Oct 18, 2009 #7
    I'm aware that there is a formula for average speed (s=d/t), but something like that wouldn't cut it for a 3 mark question, especially when there's two follow-on questions after it. The question also asks how you would measure the average speed, rather than what average speed is.

    Also, don't worry about your English, it's not that bad! ;)
     
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