The system is at rest with the spring unstretched when ? = 0. The 5-kg uniform slender bar is then given a slight clockwise nudge. The value of b is 0.4 m.

(a) If the bar comes to momentary rest when ? = 40? determine the spring constant k.

(b) For the value k = 90 N/m, find the angular velocity of the bar when ? = 25?.

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