Recent content by Mitchel Haas

  1. Mitchel Haas

    Announcement Who Were the 2017 PF Award Winners?

    It's great to see those who put a lot of effort into helping others get recognition! Great job to all!
  2. Mitchel Haas

    Maximum Speed for Circular Turns: Radius Doubling Question Explained

    Yes, this is correct, and you're using the proper reasoning. Be sure to distinguish between v1 and v2
  3. Mitchel Haas

    Maximum Speed for Circular Turns: Radius Doubling Question Explained

    The maximum uniform circular velocity, is limited by the static frictional force of the tires on the pavement. So, Newton's 2nd law gives us $$∑F = f = m a_{\text{rad}}=\frac{m v^2}{R}$$ The maximum friction for available is fmax = usm g. So, you need to consider the radial acceleration...
  4. Mitchel Haas

    Rotation of a hoop about an off-center axis

    You'll want to use conservation of energy to solve this, as it's the easiest approach. U1 + K1 + W = U2 + K2. The initial energy is just that of the height of the center of mass (2R), m g h = (.3)(9.8)(2*.2) = 1.176J. The ending energy is the rotational KE of the hoop about the axis, or (.5) I...
  5. Mitchel Haas

    How many integers to pick such that 2 of them have digit in common

    There are 9*9*8 = 648 integers which do not have a repeating digit. (1 - 9) * (0 - 9 -1) * (0 - 9 - 2) So, you must pick 649 to insure you have an integer with a repeating digit.
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