Pendulum question

1. Nov 21, 2005

ebola_virus

A pendulum has a mass of 3-kg, a length of 2 meters and swings through a (half)arc of 21.4 degrees. What is its Amplitude to the nearest centimeter ?

i don't undretand the queston; half arc? amplitude?

and how would you use kinetic/potential energy change to solve this porblem? i really don't understand this qusetion i'd really likea couple of hints and tips for this problem thanks a lot

2. Nov 21, 2005

74.66 cm