1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Diameter of bicycle tire

  1. Jan 16, 2015 #1
    1. The problem statement, all variables and given/known data
    A bicycle tire rotates at 30 radians/s. If the bicyclist travels at 10 m/s, what is the diameter of the tire?


    2. Relevant equations
    I found; for angular speed, w=v/r
    and for linear speed; v=rw
    where v=m/s
    and w=radians/s

    So if i am thinking correctly, i already know my angular speed of 30 radians/s
    and my linear speed is 10m/s
    so now i just need to find the radius or diameter of the tire.

    If i try solving for r, i get completely different answers.
    3. The attempt at a solution
    bike tire.jpg
     
  2. jcsd
  3. Jan 16, 2015 #2

    Bystander

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    How did you get the 300 in your first solution? Remember what you're solving for, and that you have to treat both sides of an equation the same way.
     
  4. Jan 16, 2015 #3
    good question.... It's been a long day here at the power plant.

    I always tend to get confused when i try to solve for certain things. i was wanting to solve for "r" by multiplying both sides by 10.

    so now i am getting; 30rad/s = 10m/s / r
    r=10/30
    r=.33

    so that is just a radius. The diameter would be .66 meters? or 66cm...?
     
  5. Jan 16, 2015 #4

    Bystander

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    You got that for the second solution, and now for the first solution. That's what I get. And, that should be the diameter.
     
  6. Jan 16, 2015 #5
    It makes much more sense when I solve for "r" the proper way... :w


    Thanks for the help
    Cheers
    Keith
     
  7. Jan 16, 2015 #6

    Bystander

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Have a happy.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Diameter of bicycle tire
Loading...