3. The 15-kg rod BC is pin-connected at B and subjected to a couple moment of M=10 Nm. The angular velocity of the rod at 0-60 is 2 rad/s. At 0-60 the spring is deformed. The length of undeformed spring is 2m. Determine the rod's angular velocity at the instant 0=75 using principle of work and energy. Note: Free body diagram must be drawn for full credit. Also, all the calculations, steps and diagrams must be shown. Otherwise, the solutions will be incoherent and zero grade will be assigned. Principle of Work & Energy must be used for solution. Otherwise, zero Grade will be assigned. (10 marks) 3m k-20 N/m 0=60 C M=10 Nm B