Eat Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Viscosity

A

the flow of a liquid, how fast a liquid flows

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Low viscosity

A

runny

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

High viscosity

A

sticky, thick

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Laminar Flow

A

At low velocities a fluid tends to flow without lateral mixing and adjacent layers slide past one another - liquid is streamlined, no abrupt changes in direction or speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Stoke’s Law relies on

A

Laminar flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Turbulent flow

A

different layers of fluid cross over and mix, there is changing speeds and directions and little eddies are formed throughout the path - this occurs when the rate of flow reaches a critical level or an obstacle is in the way

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Thixotrophy

A

Normally it doesn’t flow but when a force is exerted on it the viscosity lessens and it flows. When the force is again removed the viscosity increases and it stops flowing again (e.g. margarine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Negative thixotrophy

A

normally it flows but when a force is exerted on it it hardens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How to measure flow rates?

A

measure mass (mass flow rate) or volume (volume flow rate) collected in a time interval

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Hard material

A

a material that is not readily scratched or indented (e.g. diamond)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Stiff material

A
  • doesn’t easily change shape when a force is applied - large load causes small deformation
  • doesn’t extend much (e.g. steel)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Elastic material

A
  • retains original shape when stretched

- when an object returns to its original shape after the load is removed (e.g. rubber)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Plastic material

A
  • extends irreversibly

- when an object is deformed and doesn’t return to its original shape after the load is removed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Ductile material

A

-can be drawn into wires (e.g. copper)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Malleable material

A
  • can be deformed and moulded into shape with a force

- can be hammered into sheets (e.g. gold)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Strong material

A
  • large force is required to make it break

- high breaking stress (e.g. steel)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Brittle material

A
  • little force is required to crack and break it

- no plastic deformation (e.g. glass)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Tough material

A
  • requires lots of force to break

- high energy density (e.g. mild steel, rubber tyres)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Forces on a falling/rising ball bearing through a fluid

A

Upthrust, Viscous Drag, Weight

20
Q

Viscous drag force

A

described by the relationship known as Stoke’s law

21
Q

Archimede’s principle

A

the size of the upthrust on the ball bearing - buoyancy force on an object in a fluid is equal to the mass of the displaced fluid

22
Q

How does temperature affect the viscosity?

A

the higher the temperature the lower the viscosity

23
Q

Why are small objects used to test viscous drag and viscosity?

A

because larger objects have a big enough drag that it can’t be ignored unlike the drag on smaller objects

24
Q

Viscous drag

A
  • particles move past each other with different velocities, frictional forces between them can slow the flow
  • size of the force depends on the viscosity of the fluid
25
Q

Weak material

A

-low breaking stress (e.g. polystyrene)

26
Q

Flexible material

A

-has a low young modulus (e.g. natural rubber)

27
Q

Soft material

A

-surface is easily scratched (e.g. plastic)

28
Q

Hooke’s Law

A

Force is proportional to the extension

29
Q

Tensile

A

forces stretch the spring

30
Q

Compressive

A

forces squash the spring

31
Q

How would you identify a stiff material on a force extension graph?

A

There would be a straight line - the steeper the line the stiffer the material

32
Q

How would you identify a plastic material on a force extension graph?

A

The line would curve

33
Q

What regions can be identified on a force extension graph?

A
  • elastic region
  • elastic limit
  • limit of proportionality
  • plastic deformation
  • break point
34
Q

What is the limit of proportionality on a force extension graph?

A

the point where the material is still elastic and will return to its original shape but doesn’t act normally

35
Q

What is the elastic limit?

A

where the material turns from elastic to plastic so no longer returns to its original shape

36
Q

What is the break point?

A

the end of the line - the force will cause the material to break

37
Q

Where is the plastic deformation?

A

where the line begins to curve

38
Q

Stress

A

force per unit area

39
Q

Strain

A

ratio of extension to original length

40
Q

Refraction

A

as light/ a wave passes through a boundary into a more/less dense material it will change speed causing it to change direction

41
Q

Polarization

A

light goes in all directions however when a polarizing lens is used it blocks the light in one plane (going in one direction)

42
Q

Polarized glasses

A

stop light going in one plane, reducing the amount of light going into your eye

43
Q

Magnetic field

A

a region in which a magnet experiences a force - its direction is that in which the north seeking pole of a needle would point

44
Q

Electric field

A

a region in which a charged particle experiences a force - its direction is the direction of the force on a positively charged particle

45
Q

Electromagnetic waves

A

electric and magnetic waves - oscillate at 90° to each other and the direction of travel

46
Q

Which waves can be plane polarized?

A

only electromagnetic can be plane polarized and are affected by a polarizing filter - not longitudinal

47
Q

Polarizing filters angle

A

work at 90° to each other