Kinesiology- Basic Concepts Of Biomechanics (For Exam 1)

Front 1

Force is:

Back 1

a push or pull exerted by one material object or substance on another

Front 2

External Forces are:

Back 2

pushes or pulls on the body that arise from sources outside the body

Ex. Gravity

Front 3

Internal Forces are:

Back 3

forces that act on the body but arise from sources within the body

Ex. Muscles , ligaments, and bones

Front 4

Vector Forces are:

Back 4

A point of application on the object being acted on

Front 5

Magnitude is:

Back 5

quality of the force being exerted

Front 6

Force Vectors have:

Back 6

a point of application or “base”

an action line w/ a direction – direction and orientation.

a magnitude – amount of force being exerted

Front 7

Force of Gravity is

Back 7

always vertically downward toward the center of the earth regardless of the orientation in space of the object

Front 8

Segmental Centers of Gravity is that:

Back 8

Each segment in a body is acted upon by the force of gravity and has its own COG/COM

COG-center of gravity
COM-center of mass

Front 9

COG of Human body is located where?

Back 9

Slightly anterior to the second sacral vertebrae

Front 10

COG of human body with movements can make the COG do what?

Back 10

Fall outside the body

Front 11

The _________ the COG is to the BOS, the ________ stable the object is.

farther/closer; more/less

Back 11

The closer the COG is to the BOS, the more stable the object is.

Front 12

Newtow's 3rd Law "The Law of Reaction" is:

Back 12

For every action there is an equal and opposite reaction

Front 13

Reaction forces are:

Back 13

always in the same line and applied to the different but contacting objects.

Directions=always opposite to each other

Ex. Two touching objects either pull on each other or push on each other.

Front 14

Law of inertia is:

Back 14

An object will remain at rest unless acted upon by an unbalanced force

Object: resist both the initiation of motion and a change in motion

Front 15

Velocity is a:

Back 15

vector quantity with both magnitude (speed) and direction

Front 16

Newton's Second Law "Law of Acceleration" is the:

Back 16

Acceleration of an object is proportional to the unbalanced forces action on it and inversely proportional to the mass of that object.

Front 17

Law of Acceleration occurs when:

Back 17

1. change speed of an object
2. change in direction of movement

**Greater the mass of an object, the greater the magnitude of net force needed either to get the object moving or to change its motion

Front 18

What are the classes of levers?

Back 18

1. 1st class
2. 2nd class
3. 3rd class

Front 19

Effort Force is:

Back 19

is producing the resultant torque (force acting in the direction of the rotation.

**Always the WINNER (in producing rotation around segment)

Front 20

Resistance Force is:

Back 20

creating an “opposing” torque.

**Always the LOSER in producing rotation of a segment

Front 21

Effort Arm (EA):

Back 21

the MA for the effort force.

**MA=moment arm

Front 22

Resistance Arm (RA):

Back 22

the MA for the resistance force

**MA=moment arm

Front 23

The First Class lever is:

Back 23

when two forces are applied on either side of an axis at some distance from that axis, creating rotation in opposite directions.

Ex. Seesaw

Front 24

In 1st Class lever what is the Effort Force, Resistance Force, Effort Arm, and Resistance Arm:

Back 24

ER: force causing the motion

RF: force that is opposing the movement

EA: lever arm of the effort force

RA: lever arm of the resistance force

Front 25

Effort Arm can be larger, small, or equal to the resistance arm. T/F?

Back 25

True

Front 26

First Class Levers rarely occurs in humans but when it does is occurs where:

Back 26

1. force of the triceps muscle on the olecranon of the ulna and an external force on the ulna are separated by the axis

2. Supraspinatus on greater tubercle of humerus is on opposite side of composite axis of rotation from GH joint

Front 27

Second Class Lever is:

Back 27

When two resultant forces are applied so that the resistance lies between the effort force and the axis of rotation.

Front 28

In 2nd Class lever, the effort arm is always _______ than resistance arm.

Larger/Smaller/equal

Back 28

Larger

Front 29

Third Class Lever is:

Back 29

When forces are applied so that the effort force lies closer to the axis than does the resistance

Front 30

In a 3rd class lever, effort arm will always be ________ than Resistance Arm.

Larger/Smaller/Equal

Back 30

Smaller

Front 31

A muscle creating joint rotation of its distal segment in the direction of its pull is most often part of which class of levers?

Back 31

Third Class Levers

Front 32

Biceps brachii performing flexion of the forearm and hand against the resistance of gravity is which class of levers?

Back 32

Third Class Levers

Front 33

When a muscle is contracting "concentrically", the muscle must be moving the segment to which it is attached in the direction of its pull.

Therefore the muscle will be the effort force (EF).

Back 33

True

**Muscle length is shortening "concentrically"!! So WINNING!! (3rd Class Levers)

Front 34

When a muscle is contracting eccentrically (actively lengthening), the muscle must be acting in a direction opposite to the motion of the segment; that is, the muscle must be the resistance force (RF).

Back 34

True

(2nd Class Levers)

Front 35

When a muscle is contracting eccentrically, it generally serves to control (slow down) the acceleration of the segment produced by the effort force. T/F?

Back 35

True

(2nd Class Levers)

Front 36

When a lever is in rotational equilibrium, the muscle acting on the lever is contracting isometrically. In such a case, labeling the muscle as the effort or resistance force is arbitrary

Back 36

True

(1st Class Levers)

Front 37

Mechanical Advantage is:

Back 37

*A measure of the efficiency of the lever
*Related to the class of lever
*Used to develop an understanding of the relevance of the concept of classes of levers

Front 38

When the effort arm (EA) is larger than the resistance arm (RA), the mechanical advantage will be ________ than one.

Greater/Lesser/Equal to?

Back 38

Greater

Front 39

The magnitude of the effort force can be ______ than the magnitude of the resistance.

Larger/Smaller?

Back 39

Smaller

Front 40

When the EA is larger than RA, the mechanical advantage will be greater than one, & magnitude of the EF can be smaller than the magnitude of the resistance means?

Back 40

That a small effort force can create more torque and overcome a larger resistance

Front 41

In every second class lever, EA will always be ________ than RA since the resistance is _________ to the axis than the effort force.

Larger/Smaller; Closer/Farther

Back 41

Larger;Closer

Front 42

The second class lever is ________efficient, M Ad greater than one, although the magnitude of the ratio of EA to RA will vary.

Always/Never

Back 42

Always

Front 43

Third Class Levers, EA is always ________ than RA since the effort force lies _________ to the axis than the resistance.

Larger/Smaller; Closer/Farther

Back 43

Smaller;Closer

Front 44

M Ad of the third class lever will always be _______ than one.

Less/Greater

Back 44

Less

Front 45

Inefficient in that the magnitude of the effort required to move the lever will have to be greater than the magnitude of the resistance

Back 45

??? ASK DANIEL

Front 46

Work is:

Back 46

done by a force applied to an object whenever the force is applied in the direction of motion of the object.

W = F x D

Front 47

Moment Arm is:

Back 47

The shortest distance btw the action line & joint axis

**Found by measuring the length of a line drawn perpendicular to the force vector, intersecting the joint axis

Front 48

Moment Arm of a Muscle Force is:

Back 48

When a force is applied to its lever at an angle greater than 90°

**MA is found by extending the vector

Front 49

The MA of any force is greatest when the action line is applied at 90° to its lever. T/F?

Back 49

True

Front 50

MA of the force of gravity is always greatest when the force is applied at 90° to the lever. T/F?

Back 50

True

Front 51

Force of gravity is applied to the forearms COG.

Back 51

Front 52

Linear Force Signs are
1. Forces applied up and right are _______.
2. Forces applied down and left are ______.

Positive/Negative/Neutral

Back 52

1. Positive
2. Negative