Question

A 5 kg mass, hung onto a spring, causes the spring to stretch 7.0 cm. What is the spring constant? What is the potential energy of the spring?

Answer 1

Given,

The mass is m=5 kg.

The extensionis d=7.0 cm

The force is

F=mg

F=5x0.07=0.35N

Thus the spring constant is:

$k=\frac{F}{d}=\frac{0.35}{0.07}=\frac{5N}{m}$

The potential energy is:

$U=\frac{1}{2}kd^2=\frac{1}{2}\times5\times(0.07)^2=0.012Nm^2$