Results 1 to 3 of 3

Math Help - Angular Velocity?

  1. #1
    Newbie
    Joined
    Feb 2009
    Posts
    11

    Angular Velocity?

    I need to determine how many revolutions a 215/45 R18 tire makes in 1 second. I have determined that the diameter of the tire is roughly 22 inches. I'm not sure which conversions to use for this. Is angular velocity w=theta/time? I'm so confused on how to start this one
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Mar 2007
    Posts
    1,240

    Talking

    Angular velocity is measured in revolutions per some unit of time. For instance, your car's tachometer may measure your engine's angular velocity in RPMs, or revolutions per minute.

    Take the diameter, and use this to find the circumference. Then take the speed (not provided) of the vehicle, and convert to comparable units. (You've probably been given kilometers per hour or miles per hour. You'd want to convert to inches per minute or inches per second, probably.)

    Divide the linear distance covered, per time unit, by the circumference value. This will give you the number of circumferences which fit into that linear distance. Since one circumference corresponds to one revolution, this gives you the number of revolutions per time unit.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    Grandad's Avatar
    Joined
    Dec 2008
    From
    South Coast of England
    Posts
    2,570
    Thanks
    1
    Hello captaintoast87
    Quote Originally Posted by captaintoast87 View Post
    I need to determine how many revolutions a 215/45 R18 tire makes in 1 second. I have determined that the diameter of the tire is roughly 22 inches. I'm not sure which conversions to use for this. Is angular velocity w=theta/time? I'm so confused on how to start this one
    Angular velocity is the rate of change of the angle turned, so, yes it is theta/time.

    But if you want the number of revolutions per second, work it out by finding the (linear) distance travelled by the car (or whatever) per second, and dividing this by the circumference of the tyre ( =\pi d = 69.12 inches for a 22 inch diameter wheel).

    For example, 60 mph = 88 fps = 88\times12 inches per second. So the angular speed = \frac{88\times 12}{69.12} = 15.3 revs per second.

    Grandad
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Angular Velocity
    Posted in the Math Topics Forum
    Replies: 2
    Last Post: January 16th 2011, 06:25 PM
  2. Angular Velocity
    Posted in the Trigonometry Forum
    Replies: 5
    Last Post: May 25th 2010, 03:03 PM
  3. Angular velocity
    Posted in the Geometry Forum
    Replies: 9
    Last Post: April 13th 2010, 10:03 PM
  4. angular velocity
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: November 28th 2009, 07:01 AM
  5. angular velocity
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: November 13th 2009, 03:45 PM

Search Tags


/mathhelpforum @mathhelpforum