A pendulum with mass m = 1.4 kg and length L = 1.75 m is released from rest at an angle θi...

A pendulum with mass m = 1.4 kg and length L = 1.75 m is released from rest at an angle θi. Once the pendulum has swung to the vertical position (i.e., θ = 0), its cord runs into a small fixed obstacle. In solving this problem, neglect the size of the obstacle, model the pendulum’s bob as a particle, model the pendulum’s cord as massless and inextensible, and let gravity and the tension in the cord be the only relevant forces.

Figure P4.43

What is the maximum height, measured from its lowest point, reached by the pendulum if θi = 20°?