# What is the spring rigidity?

Did you teach physics well at school? Do you know the basic physical laws and could just take and calculate, for example, the spring stiffness? Let's start with theoretical knowledge. The spring stiffness is the coefficient connecting the elongation of the elastic body and the elastic force resulting from this elongation. The spring stiffness is also called the coefficient of elasticity or the Hooke coefficient, since the spring stiffness refers specifically to Hooke's law. What is the elastic force that is mentioned in this law? The force of elasticity is the force that arises when the body deforms and counteracts this deformation.

## Mathematical Method

How to determine the spring stiffness or,terminology of science such as physics, the coefficient of spring stiffness? To do this, you need to know a simple formula, according to which the spring stiffness is calculated. This formula, or more precisely Hooke's law, looks like this: F = | kx |, where k is the elasticity of the spring, x is the extension of the spring or, as it is also called, the value of the spring deformation. And the value indicated by the letter F, respectively, the elastic force, which we calculate. To find out what is the spring rigidity, it is necessary to measure the two other quantities indicated in the formula using standard mathematical laws. Next, simply solve an equation with one unknown.

## Experienced method

To understand how to find the spring stiffness, andmore precisely, to determine the coefficient of spring stiffness by experience, the following manipulations should be made. You need to deform the body by applying force to it. The simplest kind of deformation is compression or stretching. The stiffness coefficient shows exactly what force it is necessary to apply to the body in order to elastically deform it into unit length. We are now talking about elastic deformation, when the body takes its original shape after the effect on it. In order to conduct this visual experiment you will need the following things:

- calculator,
- a pen,
- notebook,
- spring,
- ruler,
- cargo.

So, one end of the spring is fixed vertically, andleave the second free. Measure the length of the spring and write the result in a notebook (this will be the value of x1). Hang a load weighing 100 grams to the free end of the spring and again measure the length of the spring, write down the value (x2). Calculate the absolute elongation of the spring (the difference between the values of x1 and x2). For small compressions and stretches, the elastic force is proportional to the deformation. Here we already apply Hooke's Law, according to which Fupr = | kx |, where k is the stiffness coefficient. In order to find the coefficient of rigidity we need, we must divide the tensile force by the extension of the spring. The tensile force is found as follows: Fupr = - N = -mg. It follows that mg = kx. So, k = mg / x. Then everything is simple: substitute the values you know in the formula and find out what the rigidity of the spring is.