Elasticity, Spring Constant and Hooke's Law

What 3 things could happen when a force is applied to an object?


It can compress, stretch, or bend

What is the minimum number of forces required to stretch, bend or compress an object? why?

Two - whatever the object is, we have to apply more than one force so that it will stay still, otherwise when we pull or push it, the object will move

What do we call the change in shape of an object?


Deformation

What are the two types of deformation?


Elastic deformation and inelastic deformation

What is elastic deformation?


when an object returns to its original shape after all the forces have been removed

What is inelastic deformation?


When an object does not return to its original shape after all the forces have been remove

What does the natural length of a spring refer to?


Length of the spring before any force is applied

What force acts on a spring when it's hanging - before you have applied any force?


Weight - The weight of the spring itself

Define extension.

The increase in length of a spring when it stretched

What happens when we add mass to a spring?

The extension of the spring increases

Extension is not only an increase in length, it could be a decrease in length - in what instance would this happen?


When an object is compressed

What does the term 'spring constant' refer to?


A measure of the stiffness of a spring

What is the exact definition of spring constant - what is spring constant a measure of?

The spring constant is a measure of how many Newtons (N) it would take to stretch (or compress) an object by 1 metre

What is spring constant measured in?

N/m

'Force is directly proportional to extension' - What does that mean?


As we increase the force on a spring (we add more mass), the extension will increase proportionally

How is the relationship between force, extension and spring constant expressed mathematically?
(what is the equation)

f=ke

What does a higher spring constant indicate?


More force is needed to stretch the object, and therefore the object is stiffer

What does Hooke's Law state?


Force is directly proportional to extension

What is the elastic limit/limit of proportionality?


The point where Hooke's Law no longer applies

What happens after the elastic limit/limit of proportionality is reached?


The object will undergo inelastic deformation

What does a straight line (going up or down) on a force-extension graph indicate?


Force and extension are directly proportional

What does a curved line, on a force-extension graph indicate/show?

The spring has reached its elastic limit (limit of proportionality) and is now inelastically deformed