Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Introduction To Biomechanics > Lectures 5-11 > Flashcards

Lectures 5-11 Flashcards

1
Q

What does a force do? And what does a force have?

A

It acts on an object to cause or resist a motion

Forces have a magnitude and a direction

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

What is Newton’s first law? What is the fancy name for it?

A

A body continues in a state of rest or uniform velocity unless acted upon by an external or unbalanced force

Law of inertia

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

What is Newton’s second law of motion? What is the fancy name for it?

A

A body’s rate of change of momentum is proportional to the size of the force applied and acts in the same direction as the force applied

Law of acceleration

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

What is the equation for force?

A

Force = mass x acceleration

1N = 1kg x 1m/s/s

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

Definition of weight

A

The gravitational pull that the earth exerts on a body

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

What is the equation for weight

A

Weight (N) = Mass (kg) x Acceleration due to gravity

W=mg

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

Definition of momentum

A

The quantity of motion that an object has

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

Equation for momentum?

A

Momentum = Mass x Velocity

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

Conservation of momentum (Check this, slide 14, lecture 5)

A

The momentum before will equal the momentum after unless the object is acted upon by an external force

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

Look at question, slide 18, lecture 5

A

Important question this

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

Look at lecture 5, slide 19

A

For the link between force & velocity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is Newton’s third law of motion? What is the fancy name for it?

A

For every action there is an equal and opposite reaction

Law of reaction

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

Look at pages 86 + 87 in PE book

A

For free body diagrams

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

Definition of friction

A

A force that opposes the motion of two surfaces in contact

Look at slide 13 lecture 6 definition, bit weird though

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

Equation for the coefficient of friction

A

Coefficient of friction = frictional Force / normal force

Look at slide 16, lecture 6 for the symbols

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

Recap example

A

Lecture 6, slide 17

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

Recap

A

Lecture 6, slide 17-20

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

Definition of stress

A

Stress is the force distributed over a given area

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

Equation for stress? What is stress measured in?

A

Stress (Pa) = Force (N) / Area (metres squared)

Stress is measured in pascals

Look at slide 4, lecture 7 for symbols

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Definition of strain?

A

Strain is the deformation of a tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Equation of strain?

A

Strain = change in length (m) / original length (m)

Strain = deformation / original shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the units for strain? (Check this on recap/google, slide 5, lecture 7)

A

Unitless / %

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Look at the stress ~ strain relationship slide 6, lecture 7

A

Recap it as well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Recap

A

Slide 8 - 21, lecture 7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Definition of centre of mass

A

The point at which an object or a body is balanced in all directions, the point at which weight appears to act

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Definition of (static) equilibrium

A

A state where net force acting on an object is zero

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Definition of stability

A

Stability is the ability of an object to resist a disruption to equilibrium and to return to its normal state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Tests of balance

A

Timed single leg stand

Functional reach test

29
Q

Definition of centre of pressure (CoP)

A

The point where force acts across an area

30
Q

Recap

A

Slide 7, lecture 9

31
Q

Equation for Work

A

Work (joules) = Force x Displacement

32
Q

Units of Work

A

Joules

33
Q

What are the directions of Work?

A

Positive

Negative

Isometric contractions

34
Q

In terms of directions of Work, what does positive Work mean? What type of muscular contraction is positive Work?

A

Force and displacement in the same direction

Concentric contraction

35
Q

In terms of direction of Work, what does negative Work mean? What type of muscular contraction is negative Work?

A

Force and displacement in the opposite direction

Eccentric contraction

36
Q

In terms of direction of work, what type of Work is an isometric contraction?

A

No mechanical Work

37
Q

Equation for potential energy

A

Potential energy (Joules) = Mass x Gravity x Height

38
Q

Equation for potential strain energy

A

Potential strain energy (Joules) = 1/2 proportionality constant x distance deformed squared

39
Q

What are the units for Potential Strain Energy?

A

Joules

40
Q

Equation for Kinetic Energy

A

Kinetic Energy (Joules) = 1/2 Mass x Velocity squared

41
Q

What are the units for kinetic energy?

A

Joules

42
Q

What is the conservation of energy?

A

Energy can neither be created nor destroyed, it can only be changed from one form to another

43
Q

What is the equation for Total Energy?

A

Total energy = Kinetic energy + Potential energy

44
Q

Equation for power

A

Power (Watts) = Force x Velocity

45
Q

What is the unit of Power?

A

Watt

46
Q

What are the different methods that can be used to calculate power? What is the choice of method very dependent upon?

A

Linear position transducer

Kinetic

Kinematic ~ Kinetic methods

The choice of method is very dependent upon the context

47
Q

Recap slide 9, lecture 9

A

Weird

48
Q

Equation for impulse

A

Impulse = Force x Time

Or

Impulse = Ft = /\M = m(v2-v1) = m/\v

49
Q

Equation for momentum?

A

Momentum = Mass x Velocity

50
Q

What are the applications for impulse?

A

Measure final velocity

Predict how much force you’ll need

How long do you need to apply a force for

How much less force is needed if I reduce mass

51
Q

Example questions

A

Slide 8 + 10

Lecture 10

52
Q

In terms of Impact, what is deformation?

A

Deformation occurs when impact occurs, for example the tennis/golf ball example, where it moves when hit

53
Q

In terms of restitution, what is deformation?

A

After deformation has occurred and it has returned to its normal shape

54
Q

Recap inelastic and elastic stuff

A

Slide 13, lecture 10

55
Q

Equation for coefficient of restitution

A

Coefficient of restitution (e) = square root of (bounce height/drop height)

56
Q

What is the centre of percussion?

A

The point about which a force can be applied without causing an acceleration at the centre of rotation

57
Q

What are the phases on the stress strain graph?

A

Elastic -> yield point -> plastic

58
Q

What does the elastic phase mean of the stress strain graph?

A

It is where the object is deformed but it will still return to its original shape

59
Q

What is the yield point on the stress strain graph?

A

This is the point where if stress/strain continues past this point the object will deform and not return to its original shape

60
Q

What is the plastic phase on the stress strain graph?

A

It is the point where the object has become so deformed it will not return to its original shape

61
Q

Definitions of stress and strain

A

Strain - is the relative change in shape or size of an object due to externally-applied forces

Stress - is the internal force (per unit area, etc) associated with a strain

62
Q

What does more stress result in?

A

More deformation

63
Q

Factors affecting stability

A

Mass
Height of centre of mass
Size of the base of support
Line of gravity

64
Q

How does the functional reach test work?

A

Get someone to reach out as far as they can before they feel they are going to fall over

65
Q

Factors affecting balance

A

Posture
Vision
Environment
Muscle strength

66
Q

What is Force proportional too?

A

Force is proportional to change in momentum over change in time

67
Q

How do Force and velocity link?

A

Write it out, remember from slide 19, lecture 5

Hint: what is the equation for force?

68
Q

What is a coefficient of friction value between?

A

0-1

Except in certain cases

69
Q

On the coefficient of friction graph what are the stages?

A

Static
then
Kinetic

Introduction To Biomechanics (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions