Quiz #3 Flashcards
Vav = _
displacement / DELTA t
Rate at which the position is changing
velocity
Velocity requires specification of _ and _
- displacement = _ x _
- magnitude & direction
- Vav x DELTA t
Vav = (Pf-Pi) / (Tf-Ti) OR
Vav = (Pi+1 - Pi) / (Ti+1 - Ti)
traditional “between method” of velocity calculation
Velocity is the _ of the Position-Time Graph
slope
- If +, velocity is _
- If -, velocity is _
- If 0, velocity is _
- positive
- negative
- 0
The greater the slope, the greater the _ _
velocity magnitude
Problem with traditional “between method” velocity calculation:
- corresponding time values are _ _ between actual time values
- therefore position and velocity _ _ _
- 1/2 way
- do not align
Vavi = (pi+1 - Pi-1) / (Ti+1 - Ti-1)
First central difference method of velocity calculation (@ velocity method)
@ velocity method:
- allows velocity times to line up
- _ is lost but minimized if DELTA t is small
- does not allow the calculation of the _ or _ _
- sensitivity (accuracy)
- first or last value
Neither the “between” or the “@” methods provide an _ _
instantaneous value
_ _ may only be approached with DELTA t being very small or as DELTA t approaches 0
“instantaneous” value
_ _ uses 2 DELTA t and _ _ uses 1 DELTA t therefore the _ method is closer to instantaneous
- @ method
- between method
- between
Aav = _
DELTA velocity / time
Rate at which velocity is changing
acceleration
Acceleration requires specification of _ and _
- DELTA velocity = _ x _
- magnitude & direction
- Aav x DELTA t
Aav = (Vf-Vi) / (Tf-Ti) OR
Aav = (Vi+1 - Vi) / (Ti+1 - Ti)
Traditional “between method” of acceleration calculation
Acceleration is the _ of the Velocity-Time Graph
slope
- If +, acceleration is _
- If -, acceleration is _
- If 0, acceleration is _
- positive
- negative
- 0
The greater the slope, the greater the acceleration _
magnitude
Problem with traditional “between method” acceleration calculation:
- corresponding time values are _ _ between actual time values
- therefore velocity values and acceleration values _ _ _
- 1/2 way
- do not align
Aavi = (Vi+1 - Vi-1) / (Ti+1 - Ti-1)
First central difference method of computing acceleration (@ acceleration method)
@ acceleration method:
- allows the acceleration-time values to line up
- _ is lost but, if DELTA t is small enough sensitivity problems are reduced
- does not allow for the calculation of the _, _, _, or _ acceleration values
- sensitivity (accuracy)
- first, second, second to last, & last
- A + value for an acceleration does not necessarily mean an _ in velocity
- A - value for acceleration does not necessarily mean a _ in velocity
- increase
- decrease
Direction: +
Change in Speed: increase (+)
Acceleration: _
+
Direction: +
Change in Speed: decrease (-)
Acceleration: _
-
Direction: -
Change in Speed: decrease (-)
Acceleration: _
+
Direction: -
Change in Speed: increase (+)
Acceleration: _
-
- step
- stride or cycle
- support or stance
- single
- double
- non
- swing
gait fundamentals
Gait:
The interval from one event on one leg until the same event on the same leg following contact
1 stride
Gait:
A portion of a stride from an event occurring on one leg to the same event occurring on the opposite leg
1 step
Gait:
- 2 steps = _
- in most instances, the _ _ is the event used
- 1 stride
- initial contact (heel strike)
The quantity of motion and object possesses
linear momentum
Linear momentum:
L = _
- mass & velocity
mV
Linear momentum:
Mass doesn’t typically change therefore changes in linear momentum are due to changes in _
velocity
- initial double limb stance
- single limb stance
- terminal double limb stance
- swing
- double limb stance
gait cycle
- Average velocity
- stride length
- cadence
- stance and swing pahses
gait cycle variables
Gait cycle variables:
Average velocity
- _ m/s (M: 1.43 m/s, F: 1.28 m/s)
- _ m/min (M: 84-88 m/min, F: 76-77 m/min)
- _ is the minimum healthy velocity
- 1.37 m/s
- 80-82 m/min
- 1.2 m/s
Gait cycle variables:
Stride length
- _ m (M: 1.46m, F: 1.28m)
1.41 m
Gait cycle variables:
Cadence
- _ steps/min (M: 111 steps/min, F: 117 steps/min)
113 steps/min
Gait cycle variables:
Stance and swing phase
- _ stance / _ swing
62% stance / 38% swing
stride length x 0.5 cadence = _
(V = SL x 0.5C)
velocity
Gait velocity:
Profile tendencies
- Both SL & SR increase
- Both SR & SL increase approximately linearly from a slow jog until _
7 m/s
Gait velocity:
Profile tendencies
- with relatively slow pace SL _
- SL can only increase to a _
- increases
- point
Gait velocity:
Profile tendencies
- after 7 m/s increasing _ is the main method of increasing speed
- overall _ is the key to better performance
- SR
- SR
- Age
- limb length
- disease
- osteoarthritis
- Parkinson’s
gait velocity variability
Gait velocity variability:
Age
- older adults overall have a _ variability
- HOA >/= to _
- 14 %
- 65 year olds
Gait velocity variability:
Limb length
- as children age height can account for _ of variability
4%
