PAPER 1 - Biomechanics Flashcards
Define Newton’s First law of motion : INERTIA
body continues in a STATE OF REST/UNIFORM VELOCITY unless acted upon by an EXTERNAL/UNBALANCED FORCE
Define Newton’s Second law of motion : ACCELERATION
- body’s RATE OF CHANGE in MOMENTUM = k(SIZE + Direction of FORCE applied)
Define Newton’s Third law of motion : REACTION
- every ACTION FORCE applied to a body has an EQUAL + OPPOSITE reaction force
What is the equation for VELOCITY ?
Units
displacement / time taken
m/s
What is the equation for MOMENTUM ?
Units?
- mass x velocity
kgm/s
What is the equation for ACCELERATION ?
Units?
acceleration = (final velocity - initial velocity) / time taken
m/s^2
What is the equation for FORCE ?
Units?
force = mass x acceleration
Newtons
Define FORCE
a PUSH or PULL that ALTERS a body’s state of motion
Define INERTIA
RESISTANCE of a body to CHANGE its state of motion, at rest or while moving
Define VELOCITY
the RATE OF CHANGE in DISPLACEMENT
Define MOMENTUM
the QUANTITY of MOTION possessed by a moving body
Define ACCELERATION
the RATE OF CHANGE in VELOCITY
Define WEIGHT
GRAVITATIONAL PULL that the earth exerts on a body
Define REACTION
- EQUAL+OPPOSITE FORCE in exerted by a body in response to action force placed upon it
Define FRICTION
- Force that OPPOSES the motion of TWO SURFACES in contact
Define AIR RESISTANCE
a force that OPPOSES that MOTION through the air
What are LIMB KINEMATICS ?
- study of movement in relation to TIME AND SPACE
What are FORCE PLATES ?
- measure ground reaction forces
What are the functions of WIND TUNNELS ?
- test aerodynamic efficiency
- measure air resistance
Define LINE OF GRAVITY
imaginary line that extends from CoM to the FLOOR
What is a FIRST CLASS lever ?
effort - fulcrum - load
What is a SECOND CLASS lever ?
effort - load - fulcrum
What is a THIRD CLASS lever ?
load - effort - fulcrum
What is the EFFORT ARM ?
distance from FULCRUM to EFFORT
What is the LOAD ARM ?
distance from LOAD to FULCRUM
What is MECHANICAL ADVANTAGE ?
Which lever acts at one?
- EA > LA
- 2nd class
- Large Load w/small effort
What is MECHANICAL DISADVANTAGE ?
Which lever acts as one?
- LA > EA
- small load w/large effort
- Third Class
What is an INTERNAL FORCE ?
- Force generated by the CONTRACTION of SKELETAL MUSCLE
What is an EXTERNAL FORCE ?
comes from OUTSIDE the body and acts upon it
What are the 4 examples of EXTERNAL FORCES ?
- weight
- reaction
- friction
- air resistance
What are the 5 effects of FORCE ?
- create motion
- accelerate a body
- decelerate a body
- changing direction
- changing shape
how does force CREATE MOTION ?
- football will remain at rest on the penalty spot until a force is applied to it
how does force ACCELERATE A BODY ?
the greater the force applied by the foot on the ball, the greater it accelerates towards the goal
how does force DECELERATE A BODY ?
- force of the foot on the ball = force of the ball on the foot
how does force CHANGE THE DIRECTION OF A BODY ?
as the goalkeeper dives to save a high corner shot, he will apply force from his HANDS to the BALL, changing it’s direction pushing it AWAY from the goal
how does force CHANGE THE SHAPE OF A BODY ?
- force of the ball coming into contact with NET will change the shape of the net.
What is NET FORCE ? (resultant force)
sum of all the forces acting on a body - when all individual forces are considered
Resultant Force
What happens when the net force is 0?
- No change in motion as all forces are balanced
Define BALANCED FORCES
two or more forces acting on a body that are EQUAL IN SIZE and OPPOSITE IN DIRECTION
What are UNBALANCED FORCES ?
two or more forces UNEQUAL IN SIZE + OPPOSITE IN DIRECTION
What are the 2 VERTICAL FORCES ?
- weight
- reaction
equation for WEIGHT ?
Units?
mass x acceleration due to gravity
N
What are the 2 HORIZONTAL FORCES ?
friction
air resistance
How does VELOCITY affect air resistance ?
increased velocity of cyclist = increased air resistance
How does SHAPE affect air resistance of a cyclist ?
tear-drop helmet = decreased air resistance
What is STREAMLINING ?
SMOOTH AIR FLOW created around an AERODYNAMIC shape to minimise air resistance
How does FRONTAL CROSS-SECTIONAL AREA affect air resistance ?
low crouched position of downhill skier = decreases air resistance
How does SMOOTHNESS OF SURFACE affect air resistance ?
smooth lycra suits = decreased air resistance
What is DIRECT FORCE ?
- force applied through CoM resulting in LINEAR MOTION
What is DISTANCE ? w/units
- total length covered from start to finish (m)
What is DISPLACEMENT ?
(units)
- shortest straight-line route from start to finish (m)
What is SPEED ?
units
the rate of change in DISTANCE
m/s
What is a DISTANCE/TIME graph ?
- DISTANCE travelled plotted AGAINST TIME taken
What is a SPEED/TIME graph ?
- SPEED OF MOTION plotted AGAINST the TIME taken
What is VELOCITY/TIME graph ?
- VELOCITY OF MOTION plotted against the TIME taken
What is ANGULAR MOTION ?
- movement of a body/body part in a CIRCULAR PATH about an AXIS OF ROTATION
What is an ECCENTRIC FORCE ?
a force applied OUTSIDE the CoM, resulting in ANGULAR MOTION
What is TORQUE ?
a MEASURE of the TURNING force applied to a body
What is a sporting example of linear motion ?
skeleton bob at top speed
What is a sporting example of angular motion ?
somersault, gymnastics
Where does the LONGITUDINAL AXIS run ?
from top to bottom of the body