What is Elastic Restoring Force?
- Elastic objects, such as springs, can be stretched and squashed, but they always try to return to their original form.
- This force that allows them to restore their form is called elastic restoring force.
- It is "restoring" because it will always "restore" the object back to its original form.
- If the spring is pulled it will retract in order reach its natural length.
- Similarly, if pushed back, then the spring will expand to reach its natural length once again.
- Elastic restoring force is proportional to the distance the spring has been stretched by.
- The image below shows the direction the elastic restoring force will act in order to achieve the natural length.
Hooke's Law
- The formula for elastic restoring force is:
- The spring constant is the stiffness of the spring.
- A higher spring constant means that the spring is stiffer, and a lower spring constant means that it is more flexible.
- The formula for elastic restoring force is negative, as it will always act in the opposite direction to the displacement, x.
- If you pull a spring in the positive direction (positive displacement), the elastic restoring force will pull it towards the negative direction.
- Likewise, if you pull a spring in the negative direction (negative displacement), the elastic restoring force will pull it towards the positive direction.