a) If a mass of 20.0 kg maxes out the balance and the maximum allowed spring extension is 15.0 cm, then 20.0 kg stretches the spring 15.0 cm. How can you find the spring constant from this? (Hint: The mass hangs off the spring in a spring balance, so to support the weight of the object the spring force has to be equal to mg.)

b) Use the equation for the frequency (not angular frequency!) of the motion.

-Dan