Foundations

Question 1

Why is the right-hand rule useful?

Answer 1

• tells us the orientation of the 3rd axis if we know the directions of the 1st and 2nd axes
• tells us the directionality of moments

Question 2

What axes form the Frontal (Coronal) plane?

Answer 2

Vertical & mediolateral

Question 3

What axes form the Sagittal plane?

Answer 3

Vertical & anteroposterior

Question 4

What axes form the Transverse plane?

Answer 4

Mediolateral & anteroposterior

Question 5

What axis does the Frontal plane rotate about?

Answer 5

Anteroposterior

Question 6

What axis does the Sagittal plane rotate about?

Answer 6

mediolateral

Question 7

What axis does the Sagittal plane rotate about?

Answer 7

vertical

Question 8

What is the difference between kinematics and kinetics?

Answer 8

Kinematics is the description of motion & Kinetics is the description of forces

Question 9

Define:
Displacement
Velocity
Acceleration
Angular Displacement
Angular velocity
Angular acceleration

(kinematics terms)

Answer 9

Displacement = change in distance

Velocity = change in distance/change in time

Acceleration = change in vel/change in time

Angular displacement = change in angle

Angular velocity = change in angle/change in time

Angular acceleration = change in angular vel/change in time

Question 10

What is the eq for force and the units?

Answer 10

F = mass * accel
Units: Newton

Question 11

What is the eq for moment (torque)?

Answer 11

Moment (torque) = Force * moment arm (ma) = Fd

Question 12

Define “Moment Arm”

Answer 12

PERPENDICULAR distance btwn line of action of the force and the axis of rotation

Question 13

T or F: Moments have magnitude and direction?

Answer 13

True.

CCW = +
CW = -

Question 14

Compare scalar and vector quantities

Answer 14

Scalar: have mag only, can be + or -, add algebraically if same unit)

Vector: mag & direction, usu noted with –> or underline, add by parallelogram (A+B = R)

Question 15

Roughly, where should the center of mass be in static stance?

Answer 15

S2 vertebra

Question 16

Does COM shift with weight distribution?

Answer 16

Yes.

Question 17

What is the center of gravity?

Answer 17

balance point for an object

Question 18

What is Newton’s 1st law?

Answer 18

Law of Inertia:
An object at rest will stay at rest AND an object in motion will stay in motion unless acted on by an unbalanced external force

Question 19

Is a force-couple equivocal to static equilibrium?

Answer 19

No

Question 20

What is static equilibrium?

Answer 20

Sum of forces = 0

All forces and moments acting on a system sum to 0

Question 21

What is Newton’s 2nd law?

Answer 21

Law of Acceleration:
Acceleration is produced when a force acts on a mass (F = ma)

Larger mass requires larger force to accel or decel

Question 22

What is Newton’s 3rd law?

Answer 22

Law of Reaction:
For every action, there is an equal and opposite reaction

Reaction force acts in the opposite direction, along the same line as the action force

Question 23

What is a force-couple?

Answer 23

PARALLEL forces w/ EQUAL magnitudes and OPPOSITE directions

Think: steering wheel (where the parallel forces are separated by a distance)

Question 24

What is translational motion and what are the 3 types of force systems?

Answer 24

Forces acting at 1 location

1. Collinear force system (tug a war)
2. Concurrent force system
3. Pulley force system

Question 25

What is Class 1 Lever?

Answer 25

See-saw: External force (load) and internal force (muscle) are on OPPOSITE sides, w/ fulcrum in middle

Question 26

For a Class 1 Lever, how does the MAmuscle compare to the MAexternal?

Answer 26

Can be >, <, or =

Question 27

What is an anatomical example of a Class 1 Lever?

Answer 27

Holding head in a neutral position while standing Triceps muscle

Question 28

What is a Class 2 lever?

Answer 28

Wheelbarrow: Fulcrum and internal force (muscle) are on OPPOSITE sides with the external force (load) in the middle

Question 29

For a Class 2 lever, how does the MAmuscle compare to the MA external?

Answer 29

MAmuscle > MAexternal

Question 30

What is an anatomical example of a Class 2 Lever?

Answer 30

Toe raise

Question 31

Why does a Class 2 lever provide great mechanical advantages for the body?

Answer 31

Because you can lift very heavy loads through short distances.

Question 32

What is a Class 3 lever in relationship between external force (load), fulcrum, and internal force (muscle)?

Answer 32

Fulcrum and external force (load) on Opposite sides with internal force (muscle) in middle

Question 33

What is an anatomical example of a Class 3 lever?

Answer 33

Biceps lifting a dumbell (Fulcrum = elbow

Question 34

For a Class 3 lever, how does the MAmuscle compare to the MA external?

Answer 34

MAmuscle < MAexternal

Question 35

Do class 3 levers have ow or high mechanical advantage?

Answer 35

Low

Question 36

What is the benefit of a class 3 lever?

Answer 36

Small shortening of muscle causes large movements of the segment Therefore, they are able to produce large amounts of movement with low mechanical advantage.

Question 37

Which class of lever is most common in the body?

Answer 37

Class 3

Question 38

External rotation of the shoulder is motion that occurs in the ___ plane about the ___ axis

Answer 38

Transverse, vertical

Question 39

What are examples of scalar quantities?

Answer 39

mass, distance, speed

Question 40

What are examples of vector quantities?

Answer 40

weight, displacement, velocity

Question 41

Abduction of the hip is a motion that occurs in the ___ plane about the ___ axis

Answer 41

Antero-posterior axis