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hbailey
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Homework Statement
A 2.5 kg pulley of radius 0.15m is pivoted about an axis through its center. What constant torque is required for the pulley to reach an angular speed 25rad/s after rotating 3.0 revolutions, starting from rest?
Homework Equations
torque = (mr^2)(angular acceleration)
The Attempt at a Solution
First I solved for time using t= omega/angular speed = 6(pie) rad / 25 rad/s = 0.75s.
Then, I solved for angular acceleration = 33 rad/s
Solving for torque, using the above equation, I got 1.9 m-N
The textbook I have says this is the wrong answer. What have I done?
The book says the answer is 0.47 m-N