A machinist turns the power on to a grinding wheel,at rest,at time t = 0 s.The wheel accelerates uniformly for 10 s and reaches the operating angular velocity of 38 rad/s.The wheel is run at that angular velocity for 30 s and then power is shut off.The wheel slows down uniformly at 2.1 rad/s² until the wheel stops.In this situation,the angular acceleration of the wheel between t = 0 s and t = 10 s is closest to:

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Quizplus · Accepted Answer

The angular acceleration is constant during the first 10 seconds, and is given by:$$\alpha = \frac{\omega_f - \omega_i}{t} = \frac{38 	ext{ rad/s} - 0 	ext{ rad/s}}{10 	ext{ s}} = 3.8 	ext{ rad/s}^2$$

A Machinist Turns the Power on to a Grinding Wheel,at