Physics

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no matter how i work it out, i keep getting the wrong answers. please help!!! i only have two more submissions before it closes on me.

A sample of blood is placed in a centrifuge of radius 14.0 cm. The mass of a red blood cell is 3.0 x 10^-16 kg, and the magnitude of the force acting on it as it settles out of the plasma is 4.0 x 10^-11 N. At how many revolutions per second should the centrifuge be operated?

  • Physics -

    r = .14 meter
    w = omega, angular rate in radians/sec
    Ac = w^2 r
    F = m Ac
    4*10^-11 = 3 *10^-16 (w^2)(.14)

    w^2 = 9.52 * 10^5 = 95.2 * 10^4
    w = 9.76 * 10^2 radians/second
    rev = 2 pi radians

    976 rad/s * 1 rev/2pi rad = 155 rev/s

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