Hooke’s Law Flashcards
Who is Robert Hooke?
-Discovered that when you put a load on a wire, its extension is proportional to the load that is added
-Holds true up to a point
Why does the limit of proportionality occur?
-A normal springs atoms before applying a force are in their regular or equilibrium position
-After applying a force, the atoms are shifted from their equilibrium
-The energy placed will be returned, if they return to their original shape
-If it does not return, it means the energy and not been returned but rather stored
What is Hooke’s law equation?
- Force = Spring Constant x Extension
- F = kx
What is a Tensile and a compressive force?
-Stretching a spring is known as a tensile force
-Squashing a spring is known as a compressive force
-k will always be the same
What is the difference between the Limit of Proportionality and the elastic limit?
-When the limit of proportionality is exceeded, it is no longer proportional and no longer obeys hooke’s law
-When the elastic limit is exceeded, it will not return to its original shape
-If the limit of proportionality has been exceeded but not the elastic limit, it no longer obeys Hooke’s law but does return to its original shape
What is elastic deformation?
-When the load or force on an object is removed, it will be restored to its original shape
What is plastic deformation?
-When the load or force is removed, it won’t return to its original shape
How can you manipulate a springs constant?
-If you place the springs end-to-end (The spring constant will divide by the number of springs)
-If you place the springs side-by-side (The spring constant will multiply by the number of springs)
What is the loading and unloading line on a graph?
-When applying a force or mass, we add a load
-The loading line gradient will be the same as the unloading line gradient
-The area under the loading line is the energy absorbed
-The area under the unloading line is the energy released
-The area between the two lines is the energy stored
What is spring constant?
-Measured by Newtons/metre
-It is the force needed to extend a material by a metre
What has happened to the material if the line on the graph stops?
-The material has snapped
How do you work out energy stored by a spring?
E = 1/2(Fx)
E = 1/2(kx^2)
How to recognise plastic or elastic deformation on a graph?
Elastic:
-Has not exceeded the elastic limit or returns to its original extension
Plastic:
-Has exceeded the elastic limit or does not return to its original extension
