Results 1 to 2 of 2

Math Help - trig-radians

  1. #1
    jabbott
    Guest

    trig-radians

    Can anyone explain this to me?

    A wheel has a radius of 20 cm. If it rolls 60 cm without slipping, through how many radians has it turned?

    thanks!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Apr 2005
    Posts
    1,631
    Quote Originally Posted by jabbott View Post
    Can anyone explain this to me?

    A wheel has a radius of 20 cm. If it rolls 60 cm without slipping, through how many radians has it turned?

    thanks!
    wheel of 20cm radius.
    circumference = 2pi(r) = 2pi(20) cm.

    It rolls 60 cm, so,
    60/[2pi(20)] = 3/(2pi) revolutions.

    one revolution is 2pi, so,
    [3/(2pi) rev]*[2pi / rev]
    = 3
    = 3 radians the wheel has turned. -----------answer.

    -------------------------------------
    Another way.

    One turn = 2pi radians ===>one circumference = 2pi(20) = 40pi cm.
    Let x = radians turned in traveling 60 cm.
    So, by proportion,
    2pi/(40pi) = x/60
    Cross multiply,
    2pi(60) = (40pi)x
    120pi = 40pi(x)
    x = 120pi/(40pi) = 3 radians -----------answer.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Help with trig and radians
    Posted in the Trigonometry Forum
    Replies: 10
    Last Post: July 14th 2010, 05:24 AM
  2. Trig with radians
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: April 2nd 2010, 04:05 PM
  3. Two trig question with squares and radians
    Posted in the Trigonometry Forum
    Replies: 7
    Last Post: January 24th 2010, 11:43 AM
  4. Trig and Radians
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: March 29th 2009, 02:13 PM
  5. solving trig equations (in radians)
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: April 11th 2007, 06:25 PM

Search Tags


/mathhelpforum @mathhelpforum