Answer
$K=1.0\times10^2\frac{N}{m}$
Work Step by Step
According to Hook's law;
$F=Kx$
This can be rearranged as;
$K=\frac{F}{x}$
Given that, $F=w=20N$
Hence, $K=\frac{w}{x}$
We plug in the known values to obtain:
$K=\frac{20}{0.20}=100=1.0\times10^2\frac{N}{m}$
