Linear Kinematics Flashcards
Kinematics can be defined as what?
The area of biomechanics dealing with the description of the spatial & temporal components of motion.
What are the types of motion?
- Linear (transitional) - straight-line motion
- Rotational
- Curvillinear motion - translation along a curved path
How do you define a performers position? And describe a reference system.
Define performers position using a reference system.
Reference system:
-Cartesian co-ordinate system.
-Two or three dimensional
What motion can a 2D reference system describe?
Planar motion
What does x axis = in the reference system?
Media-lateral
What does the y axis =?
Antero-posterior
What does the z axis =?
Vertical
Define a scalar quantity and give an example.
Quantities described fully buy their amount or magnitude.
E.g. Mass, distance, volume
Define vectors and give an example.
Quantities that cannot be completely described by magnitude alone.
Described by both magnitude & direction.
E.g. Velocity
What events does temporal analysis describe?
- Running time or performance.
- Duration of swing phase in place kicking.
- Temporal analysis allows all other kinematic variables to be determined e.g. velocity and acceleration.
Define displacement.
- a vector quantity
- measured in a straight line from position to position
Define distance.
- a scalar quantity
- may or may not be in a straight line
What does speed describe?
Quantifies the Tate at which movement occurs.
What does velocity describe?
Quantifies the rate at which movement occurs, incorporating time into distance & displacement measures.
What is the formula for speed?
Speed=distance/time
What is the formula for velocity?
Velocity=displacement/time
What is the unit measure for speed and velocity?
m/s
What is the unit measure for acceleration?
m/s/s
What is acceleration?
The rate of change of velocity with respect to time.
What quantity is acceleration?
Victory quantity
What is the formula for acceleration?
Acceleration=change in velocity/time
An athlete running 100m increases his velocity from 0-10m/s in3.8s. What’s his average acceleration?
2.63m/s/s
An athlete decreases his velocity from 10 to 9m/s in the final 2.7s of the race. What is his average acceleration?
0.37m/s
What do equations of motion describe?
Describe the behaviour of a moving system in relation to time.
A diver steps off a diving board 3m above the water. What velocity will he reach the water with?
-look for notes-
A cyclist isn’t ravelling at 20m/s in the peloton. In order to attempt a breakaway he accelerates at 4m/s/s for 5s. How far does he travel in this time? If the velocity remains constant, what is his lead?
-see notes-
During a race a 100m sprinter accelerates by 0.87m/s/s for a duration of 2.1s. Their velocity at the end of this time is 5.64m/s. What was their initial velocity?
7.47m/s
What is the formula to work out initial velocity?
u=v+at
What is the formula to work out displacement when deriving the equations?
s=0.5(u+v)t
Define a step.
Touchdown of one foot to next touchdown of the opposite foot.
Define step length.
Displacement covered in one step
Define step frequency.
Rate of stepping/
No.step/s
Define step velocity.
Step length x step frequency
