Forces and Elasticity

When you apply a force to an object you may cause it to

**stretch, compress or bend**To do this, you need more than one force

**acting**on the object, otherwise the object would simply move in the direction of the applied force instead of changing shapeAn object has been

**elastically deformed**if it can go back to its original shape and length after the force has been removedObjects than can be elastically deformed are called

**elastic**objectsAn object has been

**inelastically deformed**if it**doesn’t return**to its original shape and length after the force has been removed**Work**is done when a force**stretches**or**compresses**an object and causes energy to be transferred to the elastic potential energy store of the object. If it is elastically deformed. ALL this energy is transferred to the object’s elastic potential energy store

If a spring is supported at the top and then a weight is attached to the bottom, it stretches

The extension of a stretched spring is

**directly****proportional**to the load of force applied**F=ke**The spring constant depends on the

**material**that you are stretching-a**stiffer**spring has a**greater**spring constantThe equation also works for compression

There’s a limit to the amount of force you can apply to an object for the extension to keep on increasing proportionally

The graph shows force

**against**extension for an elastic objectThere is a

**maximum force**above which the graph curves, showing that extension is no longer proportional to force. This is known as**limit of proportionality**and is shown on the graph at the point marked PYou might see graphs with these axis the other way round-extension force graphs. The graph still starts with a straight part, but starts to curve upwards once you go past the limit of proportionality, instead of downwards

When you apply a force to an object you may cause it to

**stretch, compress or bend**To do this, you need more than one force

**acting**on the object, otherwise the object would simply move in the direction of the applied force instead of changing shapeAn object has been

**elastically deformed**if it can go back to its original shape and length after the force has been removedObjects than can be elastically deformed are called

**elastic**objectsAn object has been

**inelastically deformed**if it**doesn’t return**to its original shape and length after the force has been removed**Work**is done when a force**stretches**or**compresses**an object and causes energy to be transferred to the elastic potential energy store of the object. If it is elastically deformed. ALL this energy is transferred to the object’s elastic potential energy store

If a spring is supported at the top and then a weight is attached to the bottom, it stretches

The extension of a stretched spring is

**directly****proportional**to the load of force applied**F=ke**The spring constant depends on the

**material**that you are stretching-a**stiffer**spring has a**greater**spring constantThe equation also works for compression

There’s a limit to the amount of force you can apply to an object for the extension to keep on increasing proportionally

The graph shows force

**against**extension for an elastic objectThere is a

**maximum force**above which the graph curves, showing that extension is no longer proportional to force. This is known as**limit of proportionality**and is shown on the graph at the point marked PYou might see graphs with these axis the other way round-extension force graphs. The graph still starts with a straight part, but starts to curve upwards once you go past the limit of proportionality, instead of downwards