Robert Hooke observed that a piece of elastic or a spring stretches when a force pulls it. Hooke’s law explains that the same increase in the length of the spring is observed every time a fixed force is used for pulling the spring. The spring retains its original length by removing the force, and the extension becomes irreversible if it goes beyond the elastic limit of the spring.
The extension of the spring depends on the magnitude of the force employed to pull the spring. The quantitative relationship between the applied force and the corresponding stretch can be established by a linear regression analysis. The quantitative relationship between the force and the stretch is expressed as F = -k * L. The force exerted on the spring is “F,” while the amount of stretch is referred as “L” and the spring constant is represented as “k," which is dependent on the spring used in the experiment. If the spring has less elasticity, the amount of force must be higher to bring a small displacement with it, making its spring constant higher. The minus sign before the constant indicates that the displacement is in the opposite direction to the direction of the force applied. Spring constant is expressed in Newton/meter units. The above equation is valid for a spring that is stretched vertically.