# Pendulum problem

1. Aug 2, 2005

### badman

You pull a simple pendulum of length 0.215 m to the side through an angle of 3.50 ^\circ and release it.

i got 0.93, but it marked it wrong. i divided the mass over the accel of gravity, squared it and multiplied by 2pi. is this wrong?

Last edited: Aug 2, 2005
2. Aug 2, 2005

### zwtipp05

what are you trying to figure out? what is the question asking for?

3. Aug 2, 2005

### badman

oh sorry

How much time does it take the pendulum bob to reach its highest speed?
Take free fall acceleration to be g = 9.80 m/s^2.

4. Aug 2, 2005

### zwtipp05

The pendulum will be at it's highest speed when it is at the bottom of it's swing.

Also, the equation for the period of a pendulum is $$T = \sqrt \frac {m}{g}$$

5. Aug 2, 2005

### badman

yeah but the eqaution has to be multiplied by 2 pi

6. Aug 3, 2005

### zwtipp05

Why? The low point is 1/4 of the way through the arc of the pendulum. Since it takes the same time to go to the bottom as it does to go to the high point on the other side which is the same as the time to come back to the middle from the high point which is the same amount of time to finally go from the low point to the original starting point.

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