physics help 4 please!

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A solid disk (mass = 1 kg, R=0.5 m) is rolling across a table with a translational speed of 9 m/s.

a.) What must the angular speed of the disk be?
? rad/s
b.) What is the rotational KE of the disk?
? J
c.) What is the total KE of the disk?
? J
d.) The disk then rolls up a hill of height 2 m, where the ground again levels out. Find the translational and rotational speeds now.
? m/s
? rad/s

  • physics help 4 please! -

    I will be happy to critique your thinking.

  • physics help 4 please! -

    The angular speed is w = V/R
    I = moment of inertia = (1/2) M R^2
    KE(rotational) = (1/2) I w^2
    = (1/2)(1/2)M R^2(V/R)^2
    = (1/4) M V^2

    KE(ranslational) = (1/2) M V^2

    Add the two KE types for total KE

    Get to know these formulas. Others should not have to refresh your memory and do the work for oyu

  • physics help 4 please! -

    For some reason everytime I try to calculate the KE rotational I do not get the right answer. The translational speed can be used for V, right?

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