# Finding mass of an object on a spring, given Frequency

Zach_Sch

## Homework Statement

A mass m at the end of a spring oscillates with a frequency of 0.84 Hz . When an additional 730 g mass is added to m, the frequency is 0.65 Hz .

## Homework Equations

f*2pi = w
w = (k/m)^1/2
f = (1/2pi)*(k/m)^1/2

## The Attempt at a Solution

I simply used the third equation twice, rearranging to the following:
m = k/(2pi*f)^2
using this equation two different times I ended up with:
m = k / (2pi*.84)^2
m + .73 = k / (2pi*.65)^2
I solved the above equations for m and came out with the wrong answer.

Any help is greatly appreciated! Thanks in advance : )

Mentor

## Homework Statement

A mass m at the end of a spring oscillates with a frequency of 0.84 Hz . When an additional 730 g mass is added to m, the frequency is 0.65 Hz .

## Homework Equations

f*2pi = w
w = (k/m)^1/2
f = (1/2pi)*(k/m)^1/2

## The Attempt at a Solution

I simply used the third equation twice, rearranging to the following:
m = k/(2pi*f)^2
using this equation two different times I ended up with:
m = k / (2pi*.84)^2
m + .73 = k / (2pi*.65)^2
I solved the above equations for m and came out with the wrong answer.

Any help is greatly appreciated! Thanks in advance : )
Can you show your math at the end where you solve the two equations for m? That may help us spot any errors...

Zach_Sch
Can you show your math at the end where you solve the two equations for m? That may help us spot any errors...
Haha, so I attempted to solve my systems of equations three different times and got a very large negative mass, I just attempted it again and got the correct answer.