A thin uniform rod (length = 10.0 cm, mass = 250 g) is pivoted about a horizontal frictionless pin through one end of the rod. The moment of inertia of the rod through this axis is (1/3) mL2. The rod is placed at 20 degrees below the horizontal and then it is released. What is the angular acceleration of the rod at the instant it is released? (Be careful about the correct angle to use for the torque!)
a) 6.25 rad/s2
b) 19.7 rad/s2
c) 1.13 rad/s2
d) 14.1 rad/s2