Question

A spinning disk is rotating at a rate of 2 rad/s in the clockwise direction as shown in the figure. What is the direction of the angular velocity vector? If the disk is slowing down at a rate of 4 rad/s2, what is the direction of the angular acceleration vector? Find the wheel's angular velocity after 2 s. Find the angle through which the wheel has turned after 2 s in radians. Find the magnitude of the velocity (speed) of a point located at r = 20 cm from the center of the wheel after 2 s. Find the magnitude of the parallel acceleration of the point in the above part.

Answer 1

A)

Down

B)

Down

C)

w = wo + at = 2 + (4 x 2) = 10 rad/sec

D)

Theta = (10^2 - 2^2)/(2 x 4) = 12 rad

E)

Velocity, v = wr = 10 x 0.2 = 2 m/s

F)

Acceleration, a = 4 x 0.2 = 0.8 m/s^2

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