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In a sprint start:
* Force produced by muscles overcomes inertia of mass and he begins to accelerate
* Gravity, friction, and air resistance supply brakes
**Example of what principle? |
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acceleration is proportional to how
much ? the athlete applies and the time frame in which the ? is applied and is inversely proportional to the athlete's mass |
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| Formula to Newton’s 2nd Law? |
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| describes the quantity of motion |
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Definition
M = mv
mass (a measure of inertia) x velocity (speed & direction) |
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| contains the object’s current state of motion and the object’s resistance to changing its current state of motion? |
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any interaction (collision) between two objects, the total amount of linear momentum of both objects after the collision will be the same as the total amount that existed beforehand.
*This is known as? |
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Definition
| Conservation of Linear Momentum |
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| Conservation of linear momentum is related to what law? |
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| Newton's 3rd law - every action has an equal and opposite reaction. |
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| the product of force and the time that the force acts (time of application) is known as? |
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| Impulse is necessary to create what? |
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| Javelin throwers, ballet dancers and high jumpers lean backward as they plant the jumping foot before takeoff. This is an example of what? |
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| Sprinters and speedskaters use short, quick strides as they accelerate from the start to apply great force quickly and in short distance to overcome inertia. This is an example of what 2 concepts? |
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| The small forces of friction and air resistance are applied to the ball over a long time and distance, and the result is that they progressively reduce the momentum of the ball to zero. This is an example of what? |
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Definition
| Using Impulse to Slow Down and Stop |
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Term
| Lying on a bed of nails, runner's slide into home base are examples of what? |
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Definition
| Impulse and enlarging area of impact |
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| Ali's rolling with the punches, catching a waterballoon, catching a ball with glove are examples of what? |
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Definition
| Impulse and the extending area of time in which forces act on one's body |
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| Since in sports and movement, most objects have a constant mass, a change in momentum implies a change in ? |
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Definition
Velocity
M = m x v
Momentum = mass x velocity |
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| Goal of performance (from a mechanical perspective) is to manipulate ? and ? to move a specific object a certain speed in a desired direction |
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So to alter your performance, you need to alter impulse so you can change:
#1? |
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Definition
Change Force in:
magnitude
point of application
line of action |
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Term
So to alter your performance, you need to alter impulse so you can change:
#2? |
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Definition
| change time by changing the duratation of force application |
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Term
So to alter your performance, you need to alter impulse so you can change:
#3? |
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Definition
| Change both Force and Time in combination |
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Techniques in sports like throwing and
jumping are largely based on increasing
the ? of force application to increase Impulse |
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| a measure of force applied over a particular distance |
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the amount of work done in a particular
time period |
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Definition
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| 5 Components of Explosive Power |
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Definition
Slow Velocity Strength
High Velocity Strength
Rate of Force Development
Stretch Shortening Cycle
Technique/Skill |
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| Formula for Newton's 2nd Law of Acceleration? |
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Definition
F = MA
Force = Mass x Acceleration |
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Term
the ability of an object to do work
(i.e., to apply F over a D against a resistance) |
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Definition
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| 3 types of mechanical energy |
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Definition
kinetic
gravitational potential
strain |
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energy due to motion of an object
ability of a moving object to do work on whatever it collides with and in turn do work on itself |
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Definition
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| all moving objects have ? and ? energy |
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| more ? and faster = > capacity to apply F over T (i.e. Impulse) |
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| Formula for Kinetic energy |
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Definition
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| KE is directly proportional to an increase in ?, but, more importantly, it increases according to the square of ? |
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Definition
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| The lineman and the safety each have the same momentum butt the safety has twice as much ? |
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car skids and collisions
(i.e., the faster you drive, the longer it takes to stop) …
dispersal of KE (noise and heat)
…momentum conserved, but KE is not
“crushability” of modern cars …
*examples of what 2 concepts? |
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energy due to the deformation of an object (i.e., stored energy) …
objects with the ability to restore themselves back to their original shape as fast as possible …(e.g., a spring) |
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Definition
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Strain Energy:
for stretching or compressing = |
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Definition
| ½ (stiffness constant of the material) x (change in length of the object)2 |
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Term
| Pole vaulting (ie Sergei Bubka) is an example of what concept? |
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Definition
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Although kinetic energy gets used up in the deformation of objects (and athletes) and into heat and sound, all that's really happening is that one form of energy is being changed into another.
*example of what concept? |
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Definition
| Law of Conservation of Energy |
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Term
- elastic recoil
- rebound and temperature
- angle of impact
- velocity
- spin
- friction
*all concepts of what? |
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Definition
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| When the objects separate, and one or both moves away from the other, we call it a? |
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Definition
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| Measure of the ability of an object like a ball to spring back to its orignial shape after being hit by a club, bat, or reacket, or after bouncing off a floor or a wall. It's essentially a measure of "bounciness" or "resilience." |
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Definition
| Coefficient of Restitution |
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Term
a component of a contact force that acts
parallel to the surfaces in contact |
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Definition
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| a F that results when 2 objects touch each other … |
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Definition
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| 3 types of Friction between solid surfaces |
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Definition
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Friction:
F resists motion in resting objects |
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Definition
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Friction:
F develops when objects slide and rub against each other |
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Friction:
F develops when balls, etc. roll over a surface |
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F pressing 2 surfaces together - mass pressing down and earth pushing up(sled)
*factors of what type of friction? |
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Definition
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Actual contact area between 2 surfaces different size sleds
*factors of what type of friction? |
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Definition
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Nature and Type of materials in contact
Relative motion between the 2 surfaces
- easier to keep object moving than start it…
*factors of what type of friction? |
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Definition
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nature of surfaces in contact
- pressure pushing surfaces together
- diameter of rolling object
(ie bike tires … anti-lock brakes)
*factors of what type of friction? |
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Definition
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| form of stored energy when objects and athletes are raised above a planet's surface and are primarily influenced by the gravity of that planet. |
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Definition
| Gravitational potential energy |
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wt x ht above some reference such as earth …
mass x acceleration due to gravity x ht above some reference
*what type of energy? |
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Definition
| Gravitational Potential Energy |
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| Not all of kinetic energy is expressed as motion. Some kinetic energy is converted into ? and ? |
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Definition
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| All energy (kinetic, gravitational, strain) require ? |
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