Stretching Springs

• Springs are designed to stretch a long way when a small force is applied, making it easy to measure how their length changes.

Practical setup

• A spring is hung from a rigid clamp, making the top end fixed.
• Weights are hung on the end of the spring. This is called the load.
  • The load is the force (usually weight) stretching an object (a spring).
  • As the load is increased, the spring stretches and its length increases.
• Note that if the load is increased too far, the spring becomes permanently stretched and will not return to its original length. It has been inelastically deformed.

Extension of a spring

• As the force stretching the spring increases, the spring gets longer. It is crucial to consider the increase in length of the spring. This quantity is known as the extension.
  • The extension is the increased length of an object (e.g., a spring) when a load (e.g., weight) is attached to it.

Formula

$$\text{length of stretched spring}=\text{original length}+\text{extension}$$

Recording data

Table

• You are able to use a table with three columns to record the results of an experiment to stretch a spring. For example:

• The third column, the extension, is calculated by subtracting the original length from the value in the second column.

Graph

• To see how the extension depends on the load, a load-extension graph can be used.
  • Initially, the graph slopes up steadily, indicating that the extension increases in equal steps as the load increases.
  • Then, the graph starts to curve due to the load being so great that the spring has become permanently damaged. It will not return to its original length.