Objectives:
 Distinguish between linear, angular, and general motion
 Define:
 Distance and displacement
 Average speed and average velocity
 Instantaneous speed and velocity
 Name units of measurement for above definitions
 Use equations of motion for projectiles
Kinematics is the branch of dynamics concerned with the description of motion.
Ben Johnson versus Carl Lewis
Data from some of the fastest races ever
Linear motion
Rectilinear TranslationOccurs when all points on a body or object move in a straight line so the direction of motion does not change, the orientation of the object does not change, and all points on the object move the same distance.
Curvilinear TranslationOccurs when all points on a body or object move so that the orientation of the object does not change and all points on the object move the same distance.

Angular Motion
Angular or Rotary Motion: Occurs when all points on a body or object move in circles (or parts of circles) about the same fixed central line or axis..

General Motion
Animation of linear and angular motion
Is a runner 40 m from the start or 60 m from the finish?
Where does the tighthead prop and hooker line up in
rugby union?
x, y, z, rotationx, rotationy, rotationz
Slope of a positiontime graph
Comparing position and velocity graphs
SPEED vs VELOCITY
Marathon speed
Marathon ~ 42.2 km = 42200 m
Time = 2 hours 11 minutes = 131 minutes = 7860 seconds
Average Speed = 42200m / 7860 s = 5.37 m/s

What was a marathon runner's average speed in finishing the 42.2 km race in 2 hours 11 minutes? (
Ed Eyestone)
A
rowing shell was progressing across stream in the Willamette River at 8 mph relative to the water, while the river was flowing at 6 mph. What was the velocity of the shell with respect to the bank?
Pacing Example
What about changing speeds and velocities?
What does this imply for running around a curve?
Is someone accelerating when running a constant speed around a curve?
Shot Put Example
PositionTime Data
Shot Put PositionTime Data:
Time (s) 
Height (m) 

0 
0 
0.2 
1.8 
0.4 
3.2 
0.6 
4.2 
0.8 
4.8 
1.0 
5.0 
1.2 
4.8 
1.4 
4.2 
1.6 
3.2 
1.8 
1.8 
2.0 
0 
 PositionTime Graph 

VelocityTime Data
Shot Put VelocityTime Data:
Time (s) 
Velocity (m/s) 

0.1 
9 
0.3 
7 
0.5 
5 
0.7 
3 
0.9 
1 
1.1 
1 
1.3 
3 
1.5 
5 
1.7 
7 
1.9 
9 
 VelocityTime Graph 

Slope of
velocitytime graph equals acceleration
Corrected
Displacement with intial velocity and with constant acceleration
d=v_{i}t + 0.5at^{2}
Bobsled Example
Bobsled VelocityTime Data:
Describe the acceleration of the bobsled.
How far did the bobsled travel during this 5 seconds?
Time (s) 
Velocity (m/s) 

0 
20 
1 
22 
2 
24 
3 
26 
4 
28 
5 
30 

What is the average speed if you run a kilometer at 5 m/s and then walk a kilometer at 1 m/s ? (Note: 3 m/s is not correct.)
Solution
What is the average speed if you run a kilometer at 5 m/s and then walk a kilometer at 1 m/s ? (Note: 3 m/s is not correct.)
Average Speed is the distance traveled divided by the time involved. So in this
case the distance was 2 km which equals 2000 m. The total time will be the sum
of the times spent running and walking:
distance 1 km 1000 m
Time Running =  =  =  = 200 s
speed 5 m/s 5 m/s
distance 1 km 1000 m
Time Walking =  =  =  = 1000 s
speed 1 m/s 1 m/s
Total Time = 200 s + 1000 s = 1200 s
Therefore,
distance 2000 m
Average speed =  =  = 1.67 m/s
time 1200 s
