college physics
posted by Dan .
A 190 g airtrack glider is attached to a spring. The glider is pushed in 9.8 cm and released. A student with a stopwatch finds that 14 oscillations take 18.5 sec.
What is the spring constant?

frequency=1/2pi *sqrt(k/mass)
and frequency is 1/period. 
frequency= oscillations/second
f=14osc/18.5sec=0.76Hz
T= 1/f
T= 2pi/w
1/0.76Hz=2pi/w
cross multiply
w=2pi*0.76= 4.775 rad/s
w=sqrt(k/m)
square both sides
w^2=k/m
w^2 * m = k
k = w^2 * m
you have "w" and you have mass. Plug them in and find the spring constant. Don't forget to convert the mass from grams to kilograms.