## Fundamentals of Physics Extended (10th Edition)

Spring Constant $K= 89N/cm$.
We know that $P.E_{spring}=\frac{1}{2}Kx^2$ Putting the values, we get $25=\frac{1}{2}K(.075)^2$ $2\times25=k(.005625)$ $\frac{50}{.005625}=K$ or $K=8888.9$ $K=8.9\times10^3\frac{N}{m}$ As $1m=100cm$ Hence $K=8.9\times10^3\frac{N}{100cm}$ $K=89\frac{N}{cm}$