P5 - Forces And Elasticity Flashcards
What does stretching,compressing or bending do?
It transfers energy
How do you stretch,compress or bend objects?
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 shape)
What does it mean is an object is elastically deformed?
it can go back to its original shale and length after the force has been removed.
What are objects that are elastically deformed called?
Elastic objects (e.g a spring)
What does it mean is an object is inelastically deformed?
If the object doesn’t refurn to its original shape and length after the force has been removed.
When is energy transferred to the objects elastic potential energy store?
If ‘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
What is the extension directly proportional to?
Force applied / Load
When does a string stretch?
If a spring is supported at the top and then a weight is attached to the bottom, it stretches.
Equation to find the force applied on a spring
Force (N) = Spring Constant (N/m) x Extension (m)
F = ke
( The equation also works for compression (where e is just the different between the natural and compressed lengths - the compression))
What does the spring constant depend on?
The spring constant depends on the material that you are stretching - a stiffer spring has a greater spring constant.
Is there a limit of the amount of force you can apply on an object?
Yes there is a limit to the amount of force you can apply to an object for the extension to keep on increasing proportionally.
NOTE : For graph to show force against extension
Go to page 205 on the CGP book and read the bottem section to see the graph and the curve
