Materials Flashcards
What is density?
Mass/Volume
How do you work out the volume of a sphere?
4/3pir^3
What is viscosity?
The resistance to flow
If a liquid has a high viscosity, will the liquid flower faster or slower?
Slower
What is viscous drag?
The resistive force by a solid moving through a liquid
What is upthrust?
The weight of fluid displaced
How do you calculate the upthrust? (4)
Work out the volume of the object
This is equal to the fluid displaced
Calculate mass of fluid displaced (p=m/v)
Calculate the weight of fluid displaced (w=mg)
Describe the characteristics of laminar flow (3)
Same direction
Parallel layers
No abrupt change in speed
Describe the characteristics of turbulent flow (3)
Eddie currents
Mixed up layers
Abrupt change in speed
What is the limit of proportionality?
A point beyond which behaviour no longer conforms to Hooke’s law
What is the elastic limit?
A point beyond which the spring will no longer return to its original shape when the force is removed
What is the yield point?
The point at which the material starts to stretch with any extra load
What are the units for stress?
Nm^-2
Pa
What is the young modulus?
Stress/Strain
State Hooke’s law
F=kx