physics (shm)
posted by rock .
Suppose that a simple pendulum consists of a small 55.0 g bob at the end of a cord of negligible mass. Suppose that the angle between the cord and the vertical is given by
θ = (0.0800 rad) cos[(4.91 rad/s)t + ϕ].
(a) What is the pendulum's length?
units in m
(b) What is its maximum kinetic energy?
units in J

I got .41 m for L in part a and trying to figure out part B!!!