The height of a tower is measured with attaching a simple pendulum to its ceiling, whose length is barely enough to stay off the floor. The pendulum is let go from a small angle, and takes12 s to return to the similar location it started from. The tower is 35.75 m tall = L. If the pendulum mass is let go 0.3 m above the floor,
How fast is the mass travelling as it grazes the floor? ______m/s