Suppose that a simple pendulum consists of a small 71.8 g bob at the end of a cord of negligible mass. If the angle è between the cord and the vertical is given by
è = (0.0465 rad) cos[(6.52 rad/s) t + ö],
what are (a) the pendulum's length and (b) its maximum kinetic energy?
All right, I got that l=.23053m, but I'm not sure how to get b.