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    Hi, please may someone help with this question, especially part b.

    A coin of mass is 0.01 kg is placed on a horizontal turntable. the coin follows a circular path with radius 50cm, and at a constant speed without slipping. the coefficient of friction is 0.4.

    a) calculate the maximum frictional force ( I have already done this, F=0.0392)

    b) find the maximum angular speed of the turntable in revolutions per min

    Thanks
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    Use  \displaystyle F=\frac{mv^2}{r} .

    Then  v=r\omega .  \omega will be the angle that the coin moves through every second. So just convert that to rpm.
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    (Original post by albyedw)
    Hi, please may someone help with this question, especially part b.

    A coin of mass is 0.01 kg is placed on a horizontal turntable. the coin follows a circular path with radius 50cm, and at a constant speed without slipping. the coefficient of friction is 0.4.

    a) calculate the maximum frictional force ( I have already done this, F=0.0392)

    b) find the maximum angular speed of the turntable in revolutions per min

    Thanks
    The frictional force is acting as the centripetal force in this case. You can simply use the formula \displaystyle \vec{F}_{c} = mr\omega ^{2} which is obtained from N2L.
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    Oh, and don't forget that 50 \, \mathrm{cm} = 0.5 \, \mathrm{m}.
 
 
 
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