The 0.8-kg particle is attached to the system of two light rigid bars, all of which move...

The 0.8-kg particle is attached to the system of two light rigid bars, all of which move in a vertical plane. The spring is compressed an amount b/2 when θ = 0, and the length b = 0.30 m. The system is released from rest in a position slightly above that for θ = 0. (a) If the maximum value of θ is observed to be 50°, determine the spring constant k. (b) For k = 400 N/m, determine the speed v of the particle when θ = 25°. Also find the corresponding value of