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: Motion, with Two Objects.

  1. Feb 18, 2008 #1
    I tried for a really long time to try to answer this question, but I keep getting weird answers... could someone try and help me out? I know we're supposed to use the substitution method but I don't quite get how...

    Vectorville and Scalartown are 20.0 km apart.
    A cyclist leaves Vectorville and heads for Scalartown at 20.0 km/h.
    A second cyclist leaves Scalartown for Vectorville at exactly the same time at a speed of 15.0 km/h.

    a) Where will the two cyclists meet between the two towns?
    b) How much time passes before they meet (in minutes)?
  2. jcsd
  3. Feb 18, 2008 #2
    I'm not really sure what you mean by the substitution method, if you were to explain what you mean by that maybe I could give you a pointer as to how to calculate the answer that way.

    However, the way I would do it would be to realise that the two bikes could be treated as one bike travelling at 35 Km/h for a distance of 20 Km. Using good old speed = distance / time would give you the answer to part b, then you could use that to calculate the answer to part a.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook