Mechanical Principles Final Flashcards
What’s Newtons first law of motion?
law of inertia
a body at rest will stay at rest or continue at a constant velocity and in a straight line unless acted upon by an external unbalanced force
Newtons second law of motion
law of acceleration
acceleration of an object is directly proportional to the force acting on it, is in the same direction of the force acting on it, and is inversely related to the mass of the object.
Newtons third law of motion
For every action, there is an equal and opposite reaction
What is force?
Mass X acceleration
What is velocity?
displacement/time
or
v=s/t
What is speed?
d/t
or
distance/time
what is impulse?
f X t
or
change in momentum
What is acceleration?
change in velocity/ change in time
or
A=f/m
What is momentum?
mass X velocity
what is work?
force X distance
what is power?
(force X distance)/ time or work/time or force X velocity
Surface drag
drag derived from friction between the fluid and the object pasing through the fluid boundary
Wave drag
drag derived from the generation of waves at the interface between two different fluids, such as air and water
form drag
derived from a pressure differential between the lead and rear sides of a body moving through a fluid
def. of drag
collection of fluid forces that tend to oppose the action an athlete is performing
3 types of friction
static, >sliding,> rolling
what is static friction?
between the surfaces of two objects in contact with each other
is the resistive force for the initiation of movement
roughness and weight of an object
What is sliding friction?
a type of kinetic frictions
resistive force between the surfaces of two sliding objects
What is rolling friction?
type of kinetic friction
resistive force of the suface of one object rolling over the surface of another object
What is rolling friction affected by?
friction between two surfaces in contact
pressure or weight between the two surfaces
diameter of the rolling object
What is strength?
amount of force produced in a single effort
what is energy?
ability to perform work
kinetic energy def. and equation
energy in action
KE=1/2mv^2
what is potential energy?
stored energy ready for use
What is strain energy?
stored energy in obstacles that are strained but can be restored to their orginal shape
rubber band
How do you increase stability
decrease height of COG
increase BOS
increase mass
What is stability?
amount of resistance ued to prevent the loss of balance
maintaining the line of gravity within the BOS
What is lift?
a force acting on a body in a fluid in a direction perpendicular to the fluid flow
What affect drag?
increased air temp
increased humidity
increased altitude
drag def.
collection of fluid forces that tend to oppose the actions an athlete is performing
Drag forces always act in opposite direction
How do you increase apex for projectiles
increase angle of release up to 90 degrees
increase height of release
increase velocity of release
how doy you increase distance for projectiles?
increase andgle of relesase up to 45 degrees from ground
increase heigh of release
increase velocity of release
how do you increase angular momentum?
increase mass of what is rotating
shift mass away from axis of rotation
increase angular velocity
equation for potential energy
mgh
What is a projectile?
something or someone traveling through the air that will eventually hit the ground
Angle of release:
What Does it determine? And the three types of releases
Determines shape of flight path. Straight vertical, above 45° – height>distance
Below 45- distance > height
45- distance=height
Straight vertical
what is centripetal force?
inward pull
what is centrifugal force?
outward pull
angular velocity def.
rate of spin of an athlete or object
rotary inertia def
resistance to change in rotation
equation for RI
mr^2
how do you increase RI
increase mass of object to be rotated
increase radial distribution of the mass in relation to the axis of rotation
What is angular momentum?
the quantity of motion that a rotating athlete or object possesses
how do you increase angular momentum?
increase mass of object rotating
distribute mass further from the axis of rotation
increase angular velocity
angular momentum equation
mr^2 X angular vel.
RI X AV
what is the relationship between RI and ang. vel
inverse relationship
what is angular acceleration
change of rate of rotation in radius
torque
force X force arm
resistance X resistance arm
Lever classes and advantages
1st- balance
2nd- increased torque–things feel lighter
3rd- increase ROM and velocity
nonrepetitive skills
discrete skills
Shifts from one skill to another- swing bat then run
follow through is a deceleration phase
builds momentum from one skill to the next-tumbling
teach each skill separately
add additional skills and teach the rhythm and patterns when combining multiple skills
repetitive skills
skill is continuously repeated,
one complete cycle of skill leads to the next
Swimming
Open skills
skills performed in unpredictable environments
opponent attempts to foild your physical objective
Basketball game
pitches are dif every time in game
Closed skills
skills that are perfomred under predictable environments
No opponent
same required action/movement every time
Easier to train for because you can create a practice environmnent that is the same as comp.
Shooting a free throw, weight lifting-comp.
Sequential
happening one after the other
simultaneous
happens all at once
summation of forces
sum of all muscle action produce end result regarding power output
Archimedes principle
buoyant force acting on a body is equal to the weight of the fluid displaces by the body
buoyancy def.
tendency for something to float
direction always vertically upward, against gravity
What does lift increase with?
inc. in velocity of fluid flow
inc. in the surafce area of the flat side of the foil
inc. in the density of the fluid
Bernouli’s principle
inverse relationship between relative velocity and relative pressure in a fluid flow
Regions of low velocity are associated with regions of high pressure
Magnus Effect
pressure differential created by a spinning body
deviation in the trajectory of a spinning object toward the direction of spin
Inverse relationship between velocity and pressure
What is buoyancy force?
weight of water displaced by an object submerged in flui
