Answer:
128.8 N/m
Explanation:
Frequency for a spring attached oscillating mass is f=1/2π[tex]\sqrt{k/m][/tex],
where k is the stiffness of the spring (or spring constant) and m is the mass
Solving for k
f²(4[tex]\pi^{2}[/tex])=k/m
k=m(f²(4[tex]\pi^{2}[/tex]))=2000(16·4·3.14²) = 1262/9.8=128.8 N/m