Simple Harmonic Motion Problem(pendulum)

[JSmith89]

Homework Statement

A simple pendulum is made from a 0.653 m-long string and a small ball attached to its free end. The ball is pulled to one side through a small angle and then released from rest. After the ball is released, how much time elapses before it attains its greatest speed?

Homework Equations

Tpend=2$$\pi$$$$\sqrt{}length/gravity$$

incase that didn't come out right using the symbols: Timeofpend=2pi*the square root of length divided by gravity

The Attempt at a Solution

I used this equation from notes in class and the answer was wrong... I'm not sure whether you need to factor in kinetic energy/potential energy because it's asking the time before it attains the greatest speed or not. I feel like this should be an easy question. Thanks ahead of time! :-)

 

[phyzmatix]

Remember your equation gives the time for one complete oscillation. Think of where the pendulum's speed will be a maximum (at which position) during it's swing? The law of conservation of mechanical energy will help you to determine this point.

 

[JSmith89]

ok got it thanks!

 

[phyzmatix]

ok got it thanks!

Glad to be of assistance