Biomechanics part 1 Flashcards
Define Newton’s 1st law of motion (linear)?
NL1 = Inertia: A body continues in a state of rest or constant velocity unless acted upon by an external force.
M________ of I_______ is the resistance of a body to change its rotation?
Moment of Inertia
Name the force that opposes the motion of two surfaces in contact (anti-slipping force)?
Friction (N)
A push or pull that alters the state of motion/movement of a body is known as a f____ and is measured in N_______
Force, Newton’s
Ice skating pirouette: during mid flight moment of inertia is ____ and angular velocity is ____ because m___ is distributed close to the l____________ axis of rotation
low, high, mass, longitudinal
A_________ M__________ is the quantity of rotation possessed
Angular Momentum
Describe angular velocity
Rate of change in rotation (rate of spin)
Define Newton’s 2nd law of motion (linear)?
NL2 = Acceleration: A body’s change of momentum (velocity) is proportional to the size of the force applied and it acts in the same direction as the force applied.
Name the force that opposes motion through the air?
Air resistance (N)
A force applied directly through the centre of mass resulting in linear motion is called a d______ force
Direct
Define momentum.
The quantity of motion/movement possessed by a moving body
A force applied outside the centre of mass resulting in angular motion (rotation) is called an e________ force
Eccentric
Name the 4 factors affecting air resistance/drag (4S’s)?
- Size of frontal cross sectional area
- Speed
- Surface characteristics
- Shape/Streamlining
When moment of inertia is high, angular velocity is ___
low
Newton’s law of angular motion states a rotating body will continue to turn abouts its a___ of r________ with constant a_______ m___________unless acted upon by an eccentic force
axis of rotation, angular momentum
Angular motion results from an ________ force applied outside the COM
Eccentric
What is the effect that base of support has on stability?
Increased base of support = increase stability
Name the force that is the equal and opposite force exerted by a body in response to the action force placed upon it e.g. sprinter pushes foot against the starting blocks-starting blocks exert an equal and opposite force back
Reaction (measured in Newton’s)
Describe a sporting example of Newton’s third law:
Golf club exerts forward force on the ball. Ball exerts an equal and opposite force on the ball.
The force that opposes motion/movement through the air is called?
Air resistance
Name the force that is the gravitational pull of the earth on a body?
Weight (N)
What is angular velocity?
Rate of change in rotation (angular displacement)
Cyclists use lycra to improve ?
Surface characteristics-lycra suits reduce air resistance
Name the 4 factors affecting stability?
- Mass (greater the mass greater the stability e.g. sumo wrestler)
- Height of Centre of Mass (lower CoM = greater stability)
- Size of base of support (more points of contact/wider base = greater stability)
- Line of gravity/CoM (more central the line of gravity/CoM to base of support = greater stability)
When moment of inertia = low, angular velocity=?
High
Ice skating pirouette during landing phase, moment of inertia is ___ and angular velocity is ___
high , low
Name the 4 factors affecting friction (4R’s)?
- Roughness of contact surface,
- Roughness of ground surface,
- Reaction force
- tempeRature
The force that opposed the motion of 2 surfaces in contact (anti slipping force) is known as f_______ and is measured in N_______
Friction & Newton’s
Whats’s the relationship between line of gravity and stability?
More central line of gravity = increase stability
What happens to Centre Of Mass during the Fosbury Flop in high jump? Think about take-off and flight
Take off = arms raised COM higher but within body
Flight = COM located outside the body, under the bar
Which of Newton’s laws states that a body continues in a state of rest or constant velocity unless acted on by an external force?
Newton’s first law- law of inertia
Name the memory hook for the 3 axes of rotation? Give a sporting example for each axis.
Lollies, Taste, Fruity
L-Longitudinal (Longest = top to bottom-a trampolinist performing a full twist)
T-Transverse (Table football = side to side-a front somersault)
F-Fruity (Front to back-a cartwheel)
The gravitational pull of the earth on a body is known as w______ and is measured in N_______
Weight & Newton’s
How do you calculate force according to newton’s second law?
Force= Mass x acceleration
Describe moment of inertia
Resistance of a body to change its rotation
The memory hook for planes and axis is?
Tuna, Smells, Fishy (Planes)
Lollies, Taste, Fruity (Axis)
Movement of a body in a straight or curved line, where all body parts move the same distance, in the same direction over the same time is called ________ motion.
Linear
What is Centre of Mass?
Point at which weight appears to act/ where an object is balanced in all directions.
The force that opposes motion/movement through water is called d____ and is measured in N_______
Drag, Newton’s
State Newton’s Third Law of motion (linear)?
NL3 Reaction: For every action there is an equal and opposite reaction
Name the 2 factors affecting your moment of inertia (resistance to rotation)
- Mass
2. Distribution of mass from axis of rotation
The rate of change of velocity (speed) is known as a____________
Acceleration (m/s/s)
The sum of all forces acting on a body is called n__ force. This can either be balanced (zero) or unbalanced (+ or -)
Net
Spin (rotation) is created by an e________ force applied outside the centre of mass (CoM)
eccentric
Which of Newton’s Laws refers to a body’s change in momentum (acceleration) is proportional to the size and direction of the force applied.
Newton’s second law- law of acceleration
