Answer
$K=1.23\times10^{3}\frac{N}{m}$
Work Step by Step
According to Hook's law,
$F=Kx$
This can be rearranged as:
$K=\frac{F}{x}$
In the given scenario,
$F=w=mg$
Hence, $K=\frac{mg}{x}$
We plug in the known values to obtain:
$K=\frac{15(9.8)}{0.12}=1225=1.225\times 10^3=1.23\times10^3\frac{N}{m}$
