I rotate a meter stick $($mass $150$ g$)$ with a constant angular acceleration around a point $20$ cm from one of its ends as shown below. At time $$s it has angular velocity of $20$ rad$/$s; $12$ seconds later it has angular velocity of $50$ rad$/$s$.$

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a$.$ Find how many times the meter stick rotates between $$t$=0$s and t$=12$s$.$