Homework Help: Simple (supposedly) pendulum with unknown length and kinetic energy

1. Nov 30, 2004

VinnyCee

Please help, if a 60 g bob at the end of a cord (unknown length) of negligable mass and the angle $$\Theta = (0.0800 radian) cos[(4.43 radian / s.) t + \phi]$$ <---- Angle between cord and the vertical.

What are
a) the pendulum's length?

b) it's maximum kinetic energy?

2. Nov 30, 2004

Tide

The 4.3 rad/s is the angular frequency which is related to the length of the pendulum. Can you take it from there?

3. Nov 30, 2004

Justin Lazear

4. Nov 30, 2004