Question

A spiral spring extends by 5cm under a load of 60N. When the load is replaced by a steel block, the new extension is 7cm. What is the weight of the steel block

Answer 1

The Hooke's law states

$$F=kx$$

So

$$\frac{F_2}{F_1}=\frac{x_2}{x_1}$$

$$F_2=F_1\frac{x_2}{x_1}$$

$$=60\:\rm{N}\times\frac{7\:\rm{cm}}{5\:\rm{cm}}=84\:\rm{N}$$