Forces and elasticity

• An object is said to be elastic if it returns to its original shape after it has been stretched or compressed.
• When an elastic object is stretched or compressed it stores elastic potential energy.
• If an object obeys Hooke’s law, then the extension is proportional to the force applied to it.
• Hooke’s law can be stated as F = k x x, where F is the force, x is the extension and k is the spring constant.
• The spring constant of a spring is a measure of how stiff it is.