Chapter 8 Biomechanics

Question 1

Kinetics

Answer 1

forces causing movement (torque, gravity, friction etc)

Question 2

Kinematics

Answer 2

Time, space, mass of a moving system

Question 3

Force

Answer 3

any action or influence that moves and object

Question 4

Vector

Answer 4

quantity having both magnitude and direction

Question 5

Inertia

Answer 5

Property of matter that causes it to resist any change of its motion

Question 6

Torque

Answer 6

Tendency of force to produce rotation about an axis

Question 7

Friction

Answer 7

Force developed by 2 surfaces

Question 8

Velocity

Answer 8

vector that describes displacement and is measured in units (How fast something moves)

Question 9

Laws of Motion

Answer 9

1. Inertia
2. Acceleration
3. Action-Reaction

Question 10

Law of Inertia

Answer 10

Object at rest tends to stay at rest, object in motion tends to stay in motion (Ex. Your body when riding in a car)

Question 11

Law of Acceleration

Answer 11

1. Amount of acceleration depends on the force applied to it
2. Force is needed to change direction
3. Acceleration is inversely proportional to the mass of an object
   (Ex. Kicking a ball and how far it goes)

Question 12

Law of Action Reaction

Answer 12

For every action there is an equal and opposite reaction

Ex. Jumping on a trampoline

Question 13

Two actions that describe force

Answer 13

Scalar and Vector

Question 14

Scalar

Answer 14

Describes magnitude of force

Question 15

Vector

Answer 15

Describes both magnitude and direction of force

Question 16

Resultant Force

Answer 16

Net effect of two divergent forces (Ex. anterior posterior portions of deltoids flexing shoulder)

Question 17

Force Couple

Answer 17

Two forces act in an equal but opposite reaction producing rotation around an axis

Question 18

Torque involved in PT

Answer 18

Greatest strength at 90 degrees. Torque decreases as angle increase or decreases

Question 19

BOS, COG and LOG

Answer 19

Base of support, Center of Gravity and Line of Gravity

Question 20

stable Equilibrium

Answer 20

To disturb object, you must raise the center of gravity

Question 21

Unstable Equilibrium

Answer 21

When only a slight force is needed to disturb an object

Question 22

Neutral equilibrium

Answer 22

Objects COG is neither raised nor lowered when disturbed

Question 23

Ways to increase stability

Answer 23

Lower COg and widen BOS

Question 24

1st class lever

Answer 24

FAR. Axis between force and resitance. Designed for balance (ex. sternocleidomastoid)

Question 25

2nd class lever

Answer 25

ARF. Axis opposite force, resistance in the middle. Designed for power (ex. plantar flexion on tip toes)

Question 26

3rd class lever

Answer 26

AFR. Axis opposite resistance, force in the middle. Designed for ROM (ex. Elbow Joint)

Question 27

Most common lever system in the body

Answer 27

2nd class lever

Question 28

Mechanical advantage when carrying an object

Answer 28

Hold closer to body to reduce amount of resistance

Question 29

MA fromula

Answer 29

Force Arm / Resistance Arm