3 - Linear Kinematics Flashcards
What are the forms of motion and describe them?
Translation - all parts of the body move through the same distance in the same time
Rotation - all parts of the body move through the same angle at the same time
What are the two types of linear motion?
Rectilinear - translation occurs along the straight line
Curvilinear - translation occurs along the curved line
What are the two approaches in biomechanics?
Kinematics - description of motion
Kinetics - causes of motion
What is kinematics?
How far the body has moved, how fast it moves and how consistently it moves
What is the linear kinematics?
Describes the motion of the bodies that are undergoing translation motion through time
What is the centre of mass?
The point around which the mass of a body is equally distributed and through which the line of action of the weight force can be assumed to act
What is the location of the centre of mass?
When a body is in a fixed position with the line of gravity, the line is balanced and stable
How can you increase balance?
Lowering the centre of mass
Move lower limbs further apart
The location of the centre of mass can be changed by doing what?
change in body shape
movement of limbs
Why is the centre of mass important?
Determines the way the body responds to external forces
What is a scalar?
Described in terms of magnitude
What is a vector?
described in terms of magnitude and direction
What is a position?
Location in space relative to a reference
What is trajectory?
The path followed by the object in motion
What is distance and displacement?
Distance - length of trajectory
Displacement - change in position
What three things does a vector have?
Magnitude
Direction
Point fo origin
A vector can be represented graphically by?
Line of action
How can magnitude and direction be quantified?
Pythagaroeam theorem
Trigonometry
What is a distance-time graph?
Gradient = speed
Straight line means constant speed
Steeper the line, the greater the speed
What is a velocity-time graph?
Gradient = acceleration
What is velocity?
Speed in a given direction
What is the first derivative of displacement?
velocity
What is the second derivative of displacement?
acceleration
What does the gradient of a chord show on a displacement-time graph?
The gradient of a chord between the 2 points gives the average velocity over that time interval
How can running velocity be increased?
It can be increased by stride/step length or step/stride frequency
What are the common parameters of running?
stride/step length
stride/step frequency
velocity
How do we find the instantaneous velocity?
At a particular instant in time, the gradient of the tangent gives the instantaneous velocity
What is a resultant velocity?
the vector describing the net effect of all of the vectors the body is experiencing
What does uniform accelerated motion mean?
When a body experiences the same acceleration throughout an interval in time its acceleration is constant
