EXSC 350 Chap 5

Question 0

Torque (T) =

Answer 0

Fr

Force x moment arm (perpendicular distance)

Question 1

What is a Torque?

Answer 1

A moment of Force
A rotary effect created by an applied force
It is the ANGULAR EQUIVALENT of LINEAR force

Question 2

Greater T results in a ______ tendency for rotation to occur and a ______ angular acceleration.

Answer 2

Greater

Greater

Question 3

Moment Arm is _______ and ______ distance between a force’s line of action and axis of rotation

Answer 3

Perpendicular and shortest

Question 4

Any perpendicular will chance the moment arm ______

Answer 4

Length

Question 5

A Force Couple is a pair of equal and opposite forces that produce T in the _____ direction.

Answer 5

Same

Equal magnitude
Ex: cycling, steering wheel

Question 6

Tendon

Answer 6

Muscle to bone

Question 7

Ligament

Answer 7

Bone to bone

Question 8

Joint torques

Answer 8

Produce movement of body segments.

Antagonistic and Agonistic muscles working change in joint position = net T

Question 9

Joint torque direct measure example:

Answer 9

Place a strain gauge in the muscle

Question 10

Joint torque indirect example:

Answer 10

EMG

Isokinetic device

Question 11

1st Class Lever

Answer 11

Ex: neck (atlanto-occipital joint), triceps, see-saw

E F R

*Least common

Question 12

2nd Class Lever

Answer 12

Ex: Calf (MTP joint), wheelbarrow

F R E

Question 13

3rd Class Lever

Answer 13

Ex: Biceps, broom

F E* R

*Most Common in body

Mech Adv. Resistance

Question 14

Purpose of levers

Answer 14

To gain mechanical advantage

To gain a greater ROM with sm force arm movement

Question 15

Mechanical Adv. Formula

Answer 15

Force/Resistance

> 1 Gain Mech adv.
<1 Lose Mech adv.
=1 No Mech adv.

Question 16

Rotary Component

Answer 16

The only force component that will cause the bone to rotate about the joint center. Perpendicular to the bone. (Y component)

Question 17

Dislocating Component

Answer 17

The components of force that is parallel to the bone pulling the bone AWAYSATURDAY form the joint center.

(X component)

Question 18

Stabilizing Component

Answer 18

The component of force that is parallel to the bone pulling the bone TOWARD the joint center.

(X component)

Question 19

If the Angle is < 90 deg…..

Answer 19

Rotary and Dislocating components (y,x)

Question 20

If an Angle is > 90 deg…

Answer 20

Has both Rotary and Stabilizing components (y,x)

Question 21

If an Angle is at 90 deg….

Answer 21

It has 100% Rotary component

Question 22

Biceps produce the most force at what angle of a curl?

Answer 22

~80 deg

The force generated (strength) is highest

Question 23

The specific angles in which the muscle is stronger/stable __________ from person to person.

Answer 23

Varies

Question 24

Angles are in reference to the ______ compared to the bone not _____ compared to ______.

Answer 24

MUSCLES

Bone to Bone

Question 25

The _____ of the muscle determine the force generated.

Answer 25

Length

Question 26

Static Equilibrium

Answer 26

Condition when a body is completely motionless.

Implying force but no mvmt = isometric contraction

Net Vector Sum = Zero

Question 27

COG (Center of Gravity)

Answer 27

Point about which the body mass or weight is equally distributed and through which the force of gravity acts.

Important for Stability and Balance

Question 28

Mechanically, a body behaves as if all of its mass is concentrated at the __________________.

Answer 28

COG

Question 29

When analyzing the human body’s weight as a force for mechanical analyses, the vector representing that force is drawn through the body’s ___________.

Answer 29

COG

Question 30

Stability

Answer 30

Resistance to linear and/or angular acceleration

Question 31

Balance

Answer 31

Ability to control equilibrium

Question 32

(Improving Stability)

_______ body mass.

Increase ________ b/t body and contact surface

Answer 32

Increase

Friction

Question 33

(Improving Stability)

Increase _____ of support base in direction of ____ __ ____ of external force.

_________ position COG near edge of support base on the side of the oncoming external force

Answer 33

Friction; Line of action

Horizontally

Question 34

(Improving Stability)

If no external force, the you want your COG in the ______ of your support base.

Vertically positioning COG as _____ as possible

Answer 34

Middle

Low