The maximum speed of a 3.1-{\rm kg} mass attached to a spring is 0.70 m/s, and the maximum force exerted on the mass is 12 N.

What is the amplitude of motion for this mass?
Express your answer using two significant figures.

1 answer

Let A = the amplitude

k*A = 12 newtons

(1/2) kA^2 = (1/2)M*Vmax^2, with
Vmax = 0.70 m/s
M = 3.1 kg

You have two equations in two unknowns, k and A.
You should be able to take it from there