Question:The scale of a spring balance reading from 
is 
long.
A package is suspended from the balance is found to oscillate vertically
with a frequency of 
. How much does the package weigh.
Solution:
Firstly, lets convert everything to units that we know.
gives 
,
gives 
.
We can determine the spring constant, k assuming the spring is behaving
linearly where the measurements have been made using the relation 
, and hence 
.
For an object of mass m, on a spring, with spring constant k, we know that the
angular frequency, 
for small
oscillations is given by 
.
Therefore, given that we know 
, where f is the frequency of
oscillation (measured in Hz), we have 
.
The mass is then 
.