materials, hook's law and young modulus Flashcards
what is density?
mass per unit volume of an object
what is lead more dense than?
aluminium
what is sea water more dense than?
tap water
how do you find out how much more dense one substance is compared to another
- we can measure the mass of equal volumes of the two substances.
- The substance with the greater mass in the same volume is more dense
will objects made from low density materials have a low mass or a high mass?
low mass
what are the units for density
kg/ms^3
equation for density
d=m/v
how can you calculate volume of object if not given directly?
find volume of the shape the object is.
for example if object is sphere use sphere volume equation
density of aluminium in g/ms^3
2.73
density of copper in g/ms^3
8.94
what does density of a material mean?
The density of the material is the amount of substance that is packed inside the volume of the substance. The density of the material is generally lowest in its gaseous state, greater in the liquid state, and greatest in the solid state.
can dense materials be easily compressed?
no
what is deformation?
changing shape of an object
what makes an object deformed?
In order for an object to be deformed, a pair of equal and opposite forces must be applied to it.– So, by definition whenever forces are applied to an object, the object is deformed.
can some deformations return to their original shape?
yes if the force is removed
what is elastic deformations?
Once the altering force has been removed from a deformed object, the object springs back to its original for most deformations are elastic.
what is plastic deformations?
Once the altering force has been removed from a deformed object, the object remains permanently deformed
what are tension forces?
– Equal and opposite forces causing extension in an object.
what are compressive forces?
Equal and opposite forces causing compression of an object
what is hookes law?
Hooke’s Law is a principle in physics that states the force F needed to extend or compress a spring by some distance x is proportional to that distance
hookes law equation
f=kx
- F is the force producing the extension.
- x is the extension.
- k is the force constant (or spring constant)
Nm^-1
what can hookes law also tell us?
tells us the stiffness (toughness)of the spring.
what type of deformations does hookes law apply to?
only applies to elastic deformations.
according to hookes law what is the force required to extend or compress a string by a distance directly proportional to?
- According to Hooke’s law, the force required to extend or compress a spring by a certain distance is directly proportional to that distance.
- Hooke’s law is the linear relationship of displacement on stretching.