# Pendulum Frequency

## Homework Statement

A simple pendulum oscillates with frequency 2.30 Hz.
(a) What is its frequency if it accelerates at 0.500 g upward?
(b) What is its frequency if it accelerates at 0.500 g downward?

## Homework Equations

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

## The Attempt at a Solution

Won't frequency be constant? So both a and b are 2.30Hz?

G01
Homework Helper
Gold Member
If the pendulum is accelerating upward or downward the net acceleration the pendulum is experiencing will change. So, in this case, where g normally is in the formula, you must replace with the new net acceleration, call it a. So, what would the net acceleration be for each case. If you can find these values, then you can find the frequencies.

If the pendulum is accelerating upward or downward the net acceleration the pendulum is experiencing will change. So, in this case, where g normally is in the formula, you must replace with the new net acceleration, call it a. So, what would the net acceleration be for each case. If you can find these values, then you can find the frequencies.

So how about finding L? Before I just use f=2.3Hz and g=9.81 and solved for L. Is that correct?

G01
Homework Helper
Gold Member
Yes, The value of L found for when the pendulum is not accelerating will be the same in parts A and B. Nothing suggests the length of the string changes.

If the pendulum is accelerating upward or downward the net acceleration the pendulum is experiencing will change. So, in this case, where g normally is in the formula, you must replace with the new net acceleration, call it a. So, what would the net acceleration be for each case. If you can find these values, then you can find the frequencies.

So for part a g=9.81-0.5*9.81
and b would be g=9.81+0.5*9.81?

Thanks

G01
Homework Helper
Gold Member
That looks correct.