Term
| Newton's Laws of Motion in order: |
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Definition
1. inertia
2. acceleration
3. reaction |
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Term
| According to Newton's law of inertia, what is the measure of inertia? |
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Definition
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Definition
| all bodies are attracted to one another due to their masses |
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Term
| Formula for law of gravitation: |
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Definition
Fg=G x (m1m2/d2)
G=gravitation constant
=6.672x10-11 nxm2/kg2 |
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Definition
| gravity exerted to a body by the earth |
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Definition
| (mass)(gravitation acceleration) |
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| formula for magnitude of friction: |
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Definition
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| definition of sliding friction: |
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Definition
| due to relative motion of the surfaces |
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Term
| cause of sliding friction: |
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Definition
| due to relative motion of the surfaces |
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Term
| cause of rolling friction friction: |
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Definition
| temporary deformations of the surfaces |
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Term
| Definition of static friction |
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Definition
1 Ff experienced with no motion
2 maximum static friction is the force required to initiate motion |
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Term
| Definition of kinetic or dynamic friction |
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Definition
Ff Experienced during motion
Force required to maintain motion |
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Term
| Ways to minimize friction as resistance |
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Definition
Lubrication synovial fluid
Skating gliding
Tire inflation and paving |
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Term
| Ways to maximize friction as a source of propulsion |
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Definition
Cleats
Skating pushing off |
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Definition
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Term
| principle of momentum conversation: |
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Definition
if no external force, total moment remins constant
v=constant M=mv=constant |
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Term
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Definition
the acuumulated effect of force exertion over a period of time
i=Fxt
vector quantity
Unit: Ns
causes change in momentum |
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Term
| strategies for giving impulse (batting) |
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Definition
maximize impulse
maximize contact time through follow through |
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Term
| strategies for receiving impulse (landing, receiving, etc) |
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Definition
reduce impulse
reduce impulse force by increasing time
F=I/t |
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Term
| definition of mechanical work |
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Definition
force applied against a resistance
scalar quantity
unit: J (joule) |
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Term
| formula for mechanical work |
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Definition
| force x displacement (W=Fxd) |
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Term
| how is negative vs positive work determined? |
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Definition
determined by the angle of F & D
if angle is less than 90 (F and D are in same direction) it is positive
if angle is more than 90 degrees (F and D are in opposite directions) it is negative |
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Term
| muscule contraction vs work: |
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Definition
concentric contraction-positive work
eccentric contraction-negative work
isometric contraction-no work |
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Term
| definition of mechanical power: |
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Definition
rate of work (intensity of work)
Power=work/elapsed time (P=W/change in T)
Power=force x velocity
Unit is watts or j/s
scalar quantity |
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Term
| definition of mechanical energy |
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Definition
capacity to do work
unit: j
scalar
total mechanical energy =potential energy + kinetic energy |
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Term
| what is potential energy? |
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Definition
energy due to vertical position (height)
Ep=mgh |
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Term
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Definition
energy due to motion (velocity)
Ek=1/2mv^2 |
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Term
| conservation of mechanical energy: |
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Definition
if the gravity is the only eternal force acting on a system, the ME remains constant
E=Ep=Ek=const |
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Term
| mechnical work vs mechanical energy |
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Definition
| work causes changes in the mechanical energy of the system |
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Term
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Definition
| a point around which the weight of a body is balanced in all directions, =center of mass |
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Term
| methods of center of gravity location: |
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Definition
1. reaction board method
2. segmental method
3. suspension method |
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Definition
| resistance to disruption of the equilibrium |
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Term
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Definition
| ability to control equilibruim |
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| definition of base of support: |
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Definition
| area bounded by the outermost regions of contact between a body and support surfaces |
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Term
| factors affecting stability: |
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Definition
1. body mass
2. size of base of support
3. horizontal position of the center of gravity
4. vertical position of the center of gravity |
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Term
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Definition
the inertia of an object in an angular motion, the tendancy of an object to maintain the current state of angular motion, difficulty changing the state of angular motion
Unit: kg x m^2 |
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Definition
| function of mass distribution about the axis of rotation |
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Term
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Definition
distance from the axis of rotation to a point where the body's mass could be concentrated without altering its rotation characteristics
ROG does not show location of the COM |
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Term
| Moment of inertia (MOI) and radius of gyration (ROG) are dependent on what? |
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Definition
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Term
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Definition
MOI * angular acceleration
T=I *a (F=m*a)
Newtons 2nd law of angular motion: an external roque acting on a body generates angular acceleration |
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Term
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Definition
quantity of angular motion (vector)
AM-MOI x angular velocity
Unit=Kg*m^2/s |
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Term
| Angular momentum conservation: |
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Definition
total angular momentum of a system remains constant in the absence of external torques
H=constant |
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Term
| transfer of angular momentum: |
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Definition
overall H remains constant
H of each body part may change |
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