A fisherman's scale stretches 4.2 cm when a 2.9 kg fish hangs from it.

A fisherman's scale stretches 4.2 cm when a 2.9 kg fish hangs from it.
(a) What is the spring stiffness constant?
___________N/m
(b) What will be the amplitude and frequency of vibration if the fish is pulled down 2.3 cm more and released so that it vibrates up and down?
amplitude ___________cm
frequency _________Hz

a) k = F / x = 2.9 .9.8 / 0.042 = 676.6 = 680 N/m

b) T = 2π √ m/k = 0.41 s

f = 1/T = 2.4 Hz