1. Factors Influencing Movement
1. Magnitude of F or T
2. Inertial characteristics of object such as it’s mass, friction factors
3. Pathway available

2. Linear Speed Linear Velocity
Scalar quantity
how fast only
s = d/t
Donavan Bailey 100m 9.84
Michael Johnson 200m
Vector quantity
how fast and in what direction
v = d/t
stride length x stride frequency

3. Stride Length & Stride Frequency changes
with running velocity
FIGURE 10-3 on page 324 “Basic Biomechanics” 4th edition by Susan J. Hall

4. Page 280 from course text

5. Johnson vs Bailey
at 5.6 seconds in 150m Match Race: Bailey 25 strides (4.46 strides per sec) Johnson 27 strides (4.48 strides per sec)
at 1996 Olympics: Bailey for 100m (avg v = 10.16mps) Johnson 9.22 for 2nd 100m (avg v = 10.84mps)
Fastest recorded 10m segment in 100m race is 0.83 seconds giving a velocity of 12.1mps / 43.5km per hr

6. Linear Acceleration Vector quantity
changing speed OR changing direction
a = (v2 - v1)  (t2 - t1)
2 is final and 1 is initial (velocity & time)
a is directly related to Force and only occurs when Force is applied or ceases
speeding up = + slowing down = -

7. Universal Gravitation - Newton
1. Direct relationship between mass of 2 bodies and force of attraction between them
2. Indirect relationship between distance squared between 2 bodies and force of attraction between them
3. Falling bodies “attracted” to the ground by gaining 9.8mps per second
4. Upward projected bodies slow as above

8. Zero Velocity Zero Acceleration
Body at rest
No motion
1. Body at rest OR
2. Body constant v OR
3. Body not changing direction

9. Constant v Terminal v No change rare in sport Figure F.2 page 280
skydiving
air = resistive Force
g = motive Force
F resistive = F motive

10. Average v Instantaneous v
usually not a concern in study of motion
v = d/t
40-50m in 1.11sec. average v = 9.01mps
1000m in 3:30min. average v = 4.76mps
at a given point
takeoff
release
impact
Figure F.3 page 281

11. INERTIA - Newton’s 1st Law
“resistance then persistence”
1. body at rest remains so until a net Force acts to accelerate the body
2. body moves in the direction of applied constant v until - that Force is changed in magnitude or - a Force from another direction is applied

12. Projecting Objects
Muscle torques are motive Force
Air resistance is a resistive Force
gravity resistive Force then motive Force
friction may be a resistive Force

13. ACCELERATION Newton’s 2nd Law
Inertia = sluggishness/resistance to change
Inertia is directly related to mass
a = F/m
a has a direct relationship with F
a has an indirect relationship with m

14. F centripetal Reaction
Inward seeking
exerted along the path of the radius of the arc
Fc = ma (radial)
Body wants to continue on original path
greater m or v requires greater friction/grip

15. Pushing outward to get sufficient inward F centripetal to stay on the desired curved path