Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biomechanics > Forces and motion analysis > Flashcards

Forces and motion analysis Flashcards

(60 cards)

Start Studying
1
Q

Displacement equation (m)

A

Final position - initial position

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

Velocity (m/s) equation

A

Change in displacement/time taken

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

Acceleration equation (m/s^2)

A

Change in velocity/time taken (rate of change in velocity)

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

Define force

A

The pushing or pulling action that one object exerts on another, measured in Newtons

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

What is Newton’s first law?

A

Object either remains at rest or continues to move with constant momentum unless acted upon by a net force

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

Newton’s second law

A

The rate of change of momentum is proportional to the force causing it and the direction in which the force acts.

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

Force equation

A

Mass x acceleration

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

Weight equation

A

W = mg where g is 9.81m/s^2

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

Newton’s third law

A

For every action force there is a reaction force which is equal in magnitude and opposite in direction.

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

Ground reaction force

A

(GRF) is the reaction force applied by the ground to the body

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

Force platform/plate

A

Measures GRF

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

Centre of mass

A

The conceptual point where all the mass of the body can be considered to be concentrated.

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

Moment equation

A

Force x perpendicular distance (from pivot)

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

Aperture (size of hole in camera) equation

A

Focal length / diameter of hole

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

Relationship between depth of field and aperture

A

As depth of field increases, aperture decreases

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

Factors affecting projectile range

A

Release speed, release angle and release height

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

Linear momentum equation

A

Mass x Velocity (kg m/s)

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

Internal forces

A

Actions of muscles

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

External forces

A

Gravity, ground reaction force or other forces outside of the body

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

Pros of embedded force platforms (2)

A

Accurate and reliable 3D force measurements
High sampling frequency and resolution.

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

Cons of embedded force platforms (3)

A

Often restricted to indoor use and a single step
Possibly unnatural gait to target plate
Expensive

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

Triaxial accelerometer

A

Measures instantaneous acceleration
At rest will measure 1g (9.81N) due to gravity
Orientation is important

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

What are triaxial accelerometers often used to measure?

A

Physical activity
Quantity/intensity e.g. number of steps
‘Load’ monitoring

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

Pros of accelerometers

A

Cheaper than lab equipment
Easy to use
Often embedded within other devices (think stats vests)
Can monitor closer to the site of interest.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Cons of accelerometers
Valid for intended purpose? Affect the movement? Battery life Comfort
26
Impulse equations
Force x time
27
Impulse relation to change in momentum
Equal Ft = mv - mu
28
Rate of force development
Change in force / time taken
29
Friction equation
F = mewNormal Force
30
Define friction
A force that acts in opposition to the movement of one surface over another
31
Fluid friction
Object moving through fluid (Air) Aerodynamics - drag or air resistance Hydrodynamics (water) - drag or water resistance
32
Relative velocites
Velocities in the opposite directions: sum Velocities in the same direction: difference
33
What are the two types of flow?
Laminar and turbulent
34
Laminar flow
Fluid slides smoothly over Layers flow in parallel Little disruption to fluid so less resistance to movement
35
Turbulent flow
Less orderly (therefore, less predictable) Greater impact on object, slows object Boundary layer composed of vortices that increase surface friction, more disruption Common at rear of non-streamlined objects
36
Methods to reduce drag
More streamlined shape Smaller SA Slower relative velocity
37
Centre of Gravity
Distribution of weight is equal in all directions Does depend on gravitational field
38
Balance
The ability to control equilibrium (state of zero acceleration) achieved and maintained through stability.
39
Stability
The tendency of a body to remain in or return to its initial position following the application of a force. Can be passive (no muscular contraction) or dynamic (response)
40
What does passive stability depend on (4)?
Weight Area of base Horizontal distance from CoG to pivot point ^ As these increase, stability increases Heigh of the CoG above the base ^ As this decreases, stability increases.
41
Stable equilibrium
Potential energy at a minimum Work must be done to change Tendency to return to original position
42
Unstable equilibrium
Potential energy near or at maximum Very little work must be done to change Small movement takes the gravity line outside the base
43
Neutral equilibrium
Object moves but no change in potential energy
44
Modifiable factors to increase stability (5)
Keeping CoG over base of support Lowering CoG Increasing mass Extend base of support towards oncoming force Shift CoG towards oncoming force
45
Human balance
Active control to provide varying degrees of passive stability, and muscular actions to provide compensating active stability for passive insufficiencies
46
Common reflex balance mechanisms
Increasing response to severity: Ankle strategy Hip Stepping Arm
47
Angular velocity equation
Angular displacement/time omega (w) = delta(theta) / t
48
Angular acceleration equation
Change in angular velocity/time alpha = deltaomega / time
49
Moment of inertia
Rotational equivalent of mass Resistance of a body to change its state of angular motion Measure of the distribution of mass about an axis
50
Moment of inertia equation
I = mr^2 Moment of intertia (kgm^2) = Mass (kg) x r^2 (radius, m^2) Whole body inertia is the sum of all moments.
51
Angular momentum equation
H (kg m^2/s)= I (Moment of inertia) omega (angular velocity rad/s) ANGULAR VELOCITY MUST BE IN RADIANS
52
Constraints to movement and motion (6)
Movement pattern Skill Technique Style Rules and environment Human factors (strength, power, speed)
53
6 steps on gathering information
1. Determine the objective of the skill 2. Note any special characteristics 3. Study elite performers 4. Divide skill into phases 5. Divide each phase into key elements 6. Understand the mechanical reasons each key element is performed as it is
54
Step 1 of gathering information
Determine the objective of the skill - Classify each movement according to its overall performance objective Simplicity e.g. rugby pass
55
Step 2 of gathering information
Special characteristics Continuous - No specific beginning or end e.g. running Discrete - defined beginning and ending Closed - predictable environment Open - response to an unpredictable environment e.g. tennis
56
Step 3 of gathering information
Study elite performances of the skill Knowing the 'ideal' end product can sometimes help individuals see how it should be done.
57
Step 4 of gathering information
Divide skill into phases Preparation phase Execution phase Recovery phase
58
Step 5 of gathering information
Divide each phase into key elements E.g. for rugby Hold the ball in two hands Eyes on the ball Step forwards on to non-kicking foot etc
59
Step 6 of gathering information
Understand the mechanical reasons each key element is performed as it is - Balance - Stability - Technique issues (e.g. range of movement/injury causing it)
60

Biomechanics (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions