Biomechanics Flashcards
angular motion
-refers to rotation and involves movement around an axis
-occurs when a force is applied outside Centre of mass
-can involve the whole body or part of the body
-occurs due to torque(turning force) which causes an object to turn around its axis of rotation
newtons first law(angular motion)
-a rotating body will continue turning around its axis of rotation until an external rotational force is applied upon it
newtons second law(angular motion)
-the rate of change of angular momentum of a body is proportional to the force causing it and the change that takes place in the direction in which the force acts
newtons third law(action/reaction)
-when a force is applied by one body to another, the other body will exert an equal and opposite force on the other body
the law of inertia (newtons first law)
-the law of inertia states that a performer will remain stationary unless a strong enough force is applied to overcome inertia
newtons second law(law of acceleration)
-law of acceleration states that the rate of change of momentum of an object is directly proportional to the force causing the change
F=MA(force=mass x acceleration)
newtons third law(law of action/reaction)
-states that for every action there is an equal and opposite reaction
speed=
distance/time
distance=
speed x time
Centre of mass
-Centre of mass refers to the point of balance of a body
-it moves due to the body moving
factors affecting stability
height of centre of mass- the lower the centre of mass the greater the stability
area of support base- the larger the base of support the greater the stability
position of line of gravity- increased stability when it is central over the base of support
body mass- the greater the mass the greater the stability due to increased inertia
angular displacement
-angular displacement refers to the smallest change in angle between the starting and finish point
angular velocity
-angular velocity refers to the rotational speed of an object and the axis in which the object is rotating
vector quantity
-vector quantity refers to the angular displacement that is covered in a certain time
angular acceleration
-angular acceleration refers to the rate of change of angular velocity
inertia
-inertia refers to the resistance to change in motion
moment of inertia
-moment of inertia refers to the resistance of a body to angular motion(rotation)
-dependent on the mass of the body
how does the mass of the object impact the moment of inertia
-the greater the mass, the greater the resistance to change so therefore the greater the moment of inertia
how does the distribution of mass from the axis of rotation impact the moment of inertia
-the closer the mass is to the axis of rotation, the easier it is to turn because the moment of inertia is low
scalar quantity
When measurements are only described in terms of size or magnitude – mass, distance and speed
vector quantity
When measurements are described in terms of magnitude (size) and direction – weight, acceleration, displacement, velocity and momentum
Mass vs weight
mass:
-matter refers to the amount of matter or substance in our body
-Made up of bone, muscle, fat, tissue and fluid
-Measured in kg
weight:
-Force on a given mass due to gravity
-Measured in N
-Is a vector
acceleration
=change in velocity/time
-when velocity increases, positive acceleration occurs and when velocity is decreasing, negative acceleration takes place
-vector quantity
distance vs displacement
Distance:
-the length of the path the body takes as it moves from a starting position to a finish position
-Measured in metres
-Is a scalar quantity (only measures size)
Displacement:
-Shortest route in a straight line between the start and finish position
-Measured in metres
-Vector quantity (direction & size)
