Forces and matter

• Forces can change the size and shape of an object. They can stretch, squash, bend, or twist it.
• To investigate how objects deform, it is simplest to start with a spring.
• As force stretching on the spring increases, it gets longer.
• The increase of length on a spring when a load is added is called the extension.
• length of stretched spring = original length + extension
• When a load is so great, the spring can become permanently damaged meaning that it will not return to its original length.
• When drawing a graph for spring length, the graph will bend and have a line that slopes up more steeply.
• The point where the line slopes steeply is called the limit of proportionality. If the spring is stretched beyond that point, it will be permanently damaged.
• Hooke's law: The extension of a spring is proportional to the load applied to it, as long as the limit of proportionality is not exceeded.
• k represents a springs constant.
• x represents the extension.
• Hooke's law equation: F=kx
• Pressure is an upthrust.
• Pressure = force/area
• Units for pressure is Pascals (Pa).