Physics on the go Materials Section 2
This covers Viscosity, Behaviour of Solids and Flow
- Created by: Edward
- Created on: 27-12-12 15:33
View mindmap
- Materials Section 2
- Behaviour of solids
- Brittle materials
- Break suddenly without deforming plastically
- Ductile materials
- Shows plastic deformation
- The cross sectional area decreases before it breaks, ductile yielding
- Can change shape without losing strength
- Tough Materials
- Can withstand sudden impact forces without breaking
- Can be very strong and withstand great stress before breaking
- Examples include rubber, steel or kevlar
- Not brittle
- Hard materials
- Resists plastic deformation, not just from tensile stress but also from dents and scratches
- Example - Diamond
- Malleable materials
- Show large plastic deformation without breaking
- Not brittle, though not necessarily tough
- Can be reshaped without fracturing
- May lose strength
- Stiff materials
- High resistance to bending and scratching
- Llimit of proprtionality
- After this the graph starts to bend, stress and strain are no longer proportional to each other
- Elastic limit
- The point where the material starts to behave plastically
- Yield point
- The stress beyond which the material becomes plastic
- Brittle materials
- Flow
- Laminar flow
- Velocity of the flow is constant over time
- All fluid elements flow in the same direction
- Usually occurs when fluid is flowing slowly
- Turbulent flow
- Velocity of the flow varies with time
- Fluid elements get mixed up
- Fluid often flows around miniature whirlpools called Eddy currents
- Laminar flow
- Viscosity
- Viscosity of a fluid changes with temperature
- Viscosity decreases as temperature increases
- Viscous drag
- The friction between the surface of the object and the fluid
- Stokes' Law
- Viscous drag
- The friction between the surface of the object and the fluid
- F=6(pi)nrv
- n=viscosity of the fluid (Nsm^-2)
- r=radius of the object (m)
- v=the speed the object is moving at (ms^-1)
- Viscous drag
- Upthrust
- Weight of fluid displaced
- Weight=upthrust +viscous drag
- Viscosity of a fluid changes with temperature
- Behaviour of solids
Comments
No comments have yet been made