suppose a 1.50 kg object is suspended from the end of a silicone band. when the object is pulled down and released, the band vibrates at a frequency of 2.08 s-1. calculate the spring constant of this silicone band including units.

Isn't there a standard formula for this?

http://hyperphysics.phy-astr.gsu.edu/hbase/shm2.html

f= 1/2PI * sqrt(K/mass) check that.