Recent content by cloudboy

  1. C

    Find M, Mx, and My for a thin plate if density=ky

    That's strange. I thought xbar = My/M ? Maybe I am getting my limits messed up, I evaluated My from 0->3, because from 3->4 is symmetric.
  2. C

    Find M, Mx, and My for a thin plate if density=ky

    Ok I did it again making sure to get the powers correct and I got M = 44k/5. I calculated My to be 9k/2. When I divided My/M to get xbar I got 88/45 which can't be right!
  3. C

    Find M, Mx, and My for a thin plate if density=ky

    ok I watched a couple videos on youtube and this is what I came up with: M= \int_{x=-1}^2 \int_{y= 2-x}^{4- x^2} ky dydx ⇔ k\int_{y=2-x}^{4- x^2} ydy = k (y2/2) = k [(4-x^2)/2 - (2-x)/2] = k/2 [4-x^2 - 2+x] = k/2 [-x^2+x-2] then M= \int_{x=-1}^2 (k/2 [-x^2+x-2]) dx = (k/2)[(-x^3)/3 +...
  4. C

    Find M, Mx, and My for a thin plate if density=ky

    Ok I'm in my first calculus class and some of unfortunately I don't even recognize some of your notation. But I do understand somewhat and will try to use this. Thanks very much. ok i am trying to figure this out. but my density function is ky, where k is some constant. it doesn't have an x value
  5. C

    Find M, Mx, and My for a thin plate if density=ky

    It very well may, I just haven't learned anything about that yet. EDIT -- I am looking up double integrals, how would you apply it here?
  6. C

    Find M, Mx, and My for a thin plate if density=ky

    Homework Statement Set up integrals to find M, Mx, and My for the thin plate if d(x)=ky bounded by y=2-x and y = 4-x^2 or x = sqrt(4-y) Homework Equations M = \int dm = \intd(x)dA Mx = \intydm My = \intxdm The Attempt at a Solution I broke this down into three equations. x1 =...
  7. C

    Find derivative where f(x) has three products

    Thanks a lot! I got (8(x+1)(x-1)) / (3x^(1/3)) which is the right answer.
  8. C

    Find derivative where f(x) has three products

    Homework Statement Trying to find all Max and Min. F(x) = x^(2/3)(x^2 - 4) Homework Equations I know to use the product rule The Attempt at a Solution I tried and got this answer: x^(10/3) + (2(x+2)(x-2)) / 3x^(1/3)
  9. C

    Angular acceleration and moment of inertia on a pulley

    Ok I'm trying to figure out the time and I don't really know what to do
  10. C

    Angular acceleration and moment of inertia on a pulley

    torque = moment of inertia * angular acceleration so, since net force = 1n, torque = r * F, so torque = .1N*m. Angular acceleration = t / I = .667 ms/^2 is that right?
  11. C

    Angular acceleration and moment of inertia on a pulley

    I'm sorry, here is a picture So F_2 = 1N and F_1 = 2N and r = .10m
  12. C

    Angular acceleration and moment of inertia on a pulley

    Homework Statement Two forces are applied to a pulley with a moment of inertia I = .15kg*m^2. The pulley is mounted so that its frictionless axle is fixed in place. 1) What is the angular acceleration of the pulley? 2) If the pulley starts from rest, how long does it take to undergo...
  13. C

    Angular acceleration and force with constant angular velocity?

    Ok thanks a lot! I really appreciate the help. I just didn't have a firm grasp on the concept.
  14. C

    Angular acceleration and force with constant angular velocity?

    ω is constant, but it is uniformly changing direction. So there has to be an angular acceleration. edit -- but since angular acceleration = tangential accel. / r -- would angular acceleration = 0?
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