KHS 325 - TEST 2 REVIEW

40 multiple choice and short answer, 5 math problems, 2 bonus; 30% of test is old materal, 70% is new material

What is a scalar quantity?

measure that only considers magnitude

does not consider direction

ex: distance, temperature, money

What is a vector quantity?

describes both direction and magnitude

represented by arrows

ex: displacement, force, velocity, acceleration

What is position?

the linear location of an object at interest at a given instant

unit: m (meter)

What is linear distance?

measure of length of path followed by an object from initial to final

scalar quantity

unit: m (meter)

What is linear displacement?

the straight-line distance in a specific direction from starting to ending position

displacement = final distance - initial distance

vector quanitty

unit: m (meter)

What is the Pythagorean theorum?

a² + b² = c² (leg² + leg² = hypotenuse²)

used to calculate a missing side length in a right triangle

What are the trigonometric functions?

SOH CAH TOA

• sine = opp/hyp

• cosine = adj/hyp

• tangent = opp/adj

used to find a missing side length or a missing angle in a right triangle

What is vector resolution/decomposition?

breaking down a vector (the hypotenuse and angle) into components (x and y side lengths)

What is vector composition?

making a vector (the hypotenuse and angle) out of components (x and y side lengths)

How do you describe the direction of a vector?

*think of it like a graph with an x-axis and y-axis!

1st direction: angle does not touch this axis

2nd direction: angle touches this axis

ex: “35 degrees East of due North” means 35 degrees to the right of the positive y-axis

• it is NOT 35 degrees above the positive x-axis

What is speed?

rate of motion of an object; rate at which an object’s position is changing

scalar quantity

v = d/t (speed = distance/time)

unit: m/s (meters/second)

*NOTE: the “v” and “d” are not bolded!!!

What is linear velocity?

rate of change in linear position; rate of linear displacement; how fast an object moves in which direction

vector quantity

v = d/t (velocity = displacement/time)

unit: m/s (meters/second)

*NOTE: the “v” and “d” are bolded!!!

What is cyclical velocity?

v = cycle length * cycle frequency

ex: swimming velocity = stroke length (m/stroke) * stroke frequency

What can cause a change in acceleration?

change in magnitude of velocity

change in direction of velocity

What is scalar acceleration?

change in speed/elapsed time

• positive = speeding up

• negative = slowing down

unit: m/s²

What is vector acceleration?

change in velocity/elapsed time

• positive = speeding up of a positive velocity or slowing down of a negative velocity

• negative = slowing down of a positive velocity or speeding up of a negative velocity

unit: m/s²

How many degrees are in 1 revolution?

360 degrees

What is a radian?

angle with which the length of the arc becomes the same to the radius

1 radian = 57.30 degrees

What is angular position?

angular location at a given instant

unit: rad (radian)

directions: counterclockwise (+) and clockwise (-)

What is angular displacement?

change in angular position; net effect of angular motion

vector quantity

unit: rad (radian)

directions: counterclockwise (+) and clockwise (-)

What is angular velocity?

rate of change in angular position with angular displacement

ω = Δd/t (angular velocity = angular displacement/time)

unit: rad/s (radians/second)

What is angular acceleration?

α = Δω/t (rate of change in angular velocity over elapsed time

unit: rad/s² (radians/second²)

ex: ceiling fan rotation acceleration

What is the relationship between linear velocity, the radius, and angular velocity in circular motion?

v = r * ω (linear velocity = radius * angular velocity)

What are the differences in units and formulas between linear and angular quantities?

r —> θ

d —> ∆θ

v —> ω

a —> α

How do you determine if a vector acceleration is positive or negative?

double positive or double negative = positive acceleration

one positive and one negative = negative acceleration

What is linear motion?

all points on body show same trajectory; orientation of object does not change

rectlinear — straight path (ice skating)

curvilinear — curved path (skiing down hill)

What is angular motion?

rotation about an axis of rotation; orientation changes constantly

axis of rotation can be within body (lifting legs while lying down) or outside (trapeeze)

What is force?

push or pull acting on a body that causes motion

symbol: F

standard unit: N

What are 3 important properties of force?

direction

magnitude

point of application

What is pressure?

amount of force acting over a unit area

P = force / contact area

standard unit: Pa (aka N/m²)

What is torque?

rotary force that produces angular motion

T = F * moment arm

standard unit: Nm

vector quantity (uses - and +)

What is mechanical advantage?

gain of the system = output / input

What are the types of bones?

short bones

long bones

flat bones

irregular bones

How are joints classified?

either by function or structure

• synarthroses — fibrous joints; immovable

  • skull sutures, mid-radioulnar, midtibiofibular

• amphiarthroses — cartilaginous joints; slightly moveable

  • 1st sternocostal, epiphyseal plate, vertebrae, pubic symphysis

• diarthroses — synovial joints; freely moveable

  • major joints of body

What is joint stability?

ability to resist dislocation

prevents injuries to surrounding ligaments, muscles, and tendons

high stability desired —> increase via strength

What is joint flexibility?

ROMs allowed at joint; joint specific

increase via stretching

What is a motor unit?

single motor neuron + skeletal muscle fibers innervated

functional unit of muscle

all muscle fibers in one unit are the same fiber type

What is the size principle?

determines sequence of recruitment of motor units

smallest recruited first

SO —> FOB —> FG

fatigued —> recruit new motor units

What plane and axis is this?

frontal/coronal plane

antero-posterior axis (AP axis)

What plane and axis is this?

sagittal plane

medio-lateral axis (ML axis)

What plane and axis is this?

transverse plane

longitudinal axis (L axis)

What are the types of synovial joints?

1. gliding/plane

   • ex: intermetatasral, intercarpal, intertarsal, facet joints (vertebrae)

2. hinge

   • ex: humeroulnar (elbow)

3. pivot

   • ex: proximal and distal radioulnar joint, atlanto-axial joint

4. condyloid

   • ex: radiocarpal joint

5. saddle

   • ex: carpometacarpal of thumb

6. ball-and-socket

   • ex: acetabulofemoral joint, glenohumoral joint

What are types of muscle fibers?

SO

• slow-twitch oxidative

• type I

• high endurance, low max tension

FOG

• fast-twitch oxidative glycolytic

• type IIa

• lower endurance, larger max tension

FG

• fast-twitch glycolytic

• type IIb

• lowest endurance, largest max tension

What is the difference between kinematics and kinetics?

kinematics — study of description of motion; focuses on the effects

kinetics — study of action of forces/explanation of motion; focuses on the cause of motion

summary: description vs explanation

What are the main themes of biomechanics?

safety

effectiveness

efficiency