UNIT 2 (biomechanical principles) Flashcards
what is force
a push or pull movement that alters the state of motion of a body
what can a force cause to happen to a body
change direction
accelerate
decelerate
change an objects shape
what are the units for force, mass and acceleration
newtons (N)
kilograms (KG)
meters per second squared m/s^2
what are internal forces
forces produced by concentric muscle contraction
what are external forces
things such as gravity, air/water resistance, friction and ground reaction force
what are the types of motion
linear, angular and general
what is linear motion
motion in a straight line which all body parts moving the same distance at the same speed in the same direction
what is angular motion
circular movement around a fixed point/ axis
what Is general motion
movements which are a combination of linear and angular motion
what are the 3 laws of motion
law of inertia
law of acceleration
law of action and reaction
what is the law of inertia
an object will remain at rest or in motion in a straight line until acted on upon an external force
what is the law of acceleration
F=MA
acceleration is directly proportional to force applied and inversely proportional to the mass.
what is the law of action and reaction
for every action there is an equal and opposite reaction.
what is the equation for distance
Distance=speed x time
if a force is applied through the middle of an object (through centre of mass), what type of motion will it have
linear motion
if a force is applied off the centre of mass what type of motion will the object have
angular motion
what is momentum
a quantity of motion, it is a product of Mass and velocity.
what is velocity
it is the speed something is moving in a direction
what is impulse
the product of force and time it takes to apply the force.
impulse equation
impulse=force x time
what is net impulse
overall change in momentum of an object. it is the positive impulse - negative impulse
when does positive impulse occur
when force is applied in the same direction of motion, this will increase its velocity
when does negative impulse occur
when a force is applied in the opposite direction of motion, this will decrease its velocity
how does impulse affect momentum
a overall positive impulse will increase momentum as it increases the velocity.
an overall negative impulse will decrease momentum because it decreases velocity
how can a performer increase impulse
-increase the force applied
-increase the time force is applied for
-combining both force and time
how an a hammer thrower increase the impulse
apply a greater force by moving the arm faster therefore becoming stronger.
OR
apply the force for longer by spinning and releasing the hammer at the last moment.
what is stability
the ability of a body to return to equilibrium after being displaced
what is centre of mass
the point at which the body is balanced in all direction
what can centre of mass also be called
centre of gravity
what is the line of gravity
imaginary line which passes vertically from the centre gravity to the ground below the object
is an object with a larger base of support more stable or less stable?
more stable
what factors effect stability
mass of object
size of base of support
height of centre of mass
points of contact
how does the mass of an object effect stability
heavier objects have a greater stability because there inertia is greater.
how does size of base of support effect stability
a larger base of support increases stability because it allows the centre of mass to remain in the area more easily
how does height of the centre of mass effect stability
lower centre of mass enhances stability because the closer the centre of mass to the ground the less leverage there is for forces to move it outside the base of support
how does the number of contacts with the floor increase stability
more points of contact increases stability because it increases their base of support.
