# Simple pendulums

#### alyse!!

1. The problem statement, all variables and given/known data

A simple pendulum is made from a 0.67 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?

2. Relevant equations

f=frequency
f=(1/2pi)(g/L)^.5

f=1/T
where T=period

3. The attempt at a solution

f=1/T

f=(1/2pi)((9.8m/s^2)/0.67m))^.5
f=6.007

f=1/T
6.007=1/T
T=1/6.007
T=.166s

This is the answer that i got but it is wrong and i do not know why, and now how to do it if this is the wrong way.

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Mentor

#### jix

Redo the calculation, perhaps, and divide period by 4, since reaching the bottom takes one-quarter of the period.

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