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Math Help - why am i getting this answer

  1. #1
    prs
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    why am i getting this answer

    Q1. The rear wheels of a car are 650mm in diameter. If the wheels make 5505 turns in 3 minutes, find: the average speed in meters per second of a point on the circumference of one of the tyres.
    This how I did it: Radius=650mm divided by 2=325mm.
    325mm divided by 1000=0.325m.
    2x3.14x0.325m=2.041m.
    5505x2.041=11235.705m.
    3min x 60sec, =180seconds.
    11235 divided by 180=62.41m/s
    So I get 62.41m/s but the answer says 6.24m/s where am I going wrong.
    (i know i should have done better at school)
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  2. #2
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    Quote Originally Posted by prs View Post
    Q1. The rear wheels of a car are 650mm in diameter. If the wheels make 5505 turns in 3 minutes, find: the average speed in meters per second of a point on the circumference of one of the tyres.
    This how I did it: Radius=650mm divided by 2=325mm.
    325mm divided by 1000=0.325m.
    2x3.14x0.325m=2.041m.
    5505x2.041=11235.705m.
    3min x 60sec, =180seconds.
    11235 divided by 180=62.41m/s
    So I get 62.41m/s but the answer says 6.24m/s where am I going wrong.
    (i know i should have done better at school)
    Your calculations and your final result are OK!

    (Seems to be a typo in your book)
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  3. #3
    prs
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    bloody hell thanks earboth, after further calculations your right it should read 550 turns of the wheel and not 5505 like it says,

    thanks again p, i,ll let the college know,
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