# Deformation and Compression ## What is Deformation? - Forces don't just change the motion of objects — they can also change their **size and shape** - This change in size or shape is called **deformation**

Deformation is the change in size or shape of an object when forces are applied to it

## Types of Forces That Cause Deformation - Forces applied in opposite directions can either stretch or compress an object - The type of deformation depends on the direction of the forces ### Tensile Forces - When two forces **stretch** an object, they are described as **tensile forces** - Tensile forces pull the material apart, increasing its length - Think of pulling a rubber band between your hands — you're applying tensile forces

Tensile forces are forces that stretch a material by pulling it in opposite directions

### Compressive Forces - When two forces **compress** an object, they are known as **compressive forces** - Compressive forces push the material together, decreasing its length - Think of squeezing a sponge between your palms — you're applying compressive forces

Compressive forces are forces that compress a material by pushing it from opposite directions

## Deformation in Springs ### Applying Tensile Forces to a Spring - When a force (load) is applied to a spring, it produces a tensile force - This tensile force causes the spring to **extend** - The spring gets longer as it stretches - Example: Hanging a weight from a vertical spring causes it to extend downwards ### Applying Compressive Forces to a Spring - When a force is applied in the opposite direction, the spring **compresses** - The spring gets shorter as it's squashed together - Example: Placing a weight on top of a spring resting on a surface causes it to compress

The same spring can experience both extension and compression depending on the direction of the applied force

## Key Terminology | Term | Definition | |------|------------| | **Deformation** | Change in size or shape of an object due to applied forces | | **Tensile** | Relating to forces that stretch or pull apart a material | | **Compressive** | Relating to forces that compress or push together a material | | **Extension** | The increase in length of a material when stretched | | **Compression** | The decrease in length of a material when compressed | ## Practical Examples - **Bridge cables under tension**: The cables supporting a suspension bridge experience tensile forces from the weight of the bridge deck - **Building columns under compression**: The vertical columns in a building experience compressive forces from the weight of the floors above - **Car suspension springs**: When a car goes over a bump, the suspension springs compress and then extend - **Bungee jumping cord**: As the jumper falls, the bungee cord extends under tensile forces

Excessive deformation can cause permanent damage or failure of materials