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equilibrium
experiencing zero net force
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equilibrium position
When nothing is pushing or pulling on the spring, and the free end is in equilibrium at a particular position
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stable equilibrium
the end of the spring when it naturally returns to its equilibrium position if it is stretched or compressed
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Hooke's law
- The stiffer the spring and the farther you stretch it, the harder it pulls back
- F = -kx
- restoring force = -spring constant x distortion
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spring constant
k, measure of the spring's stiffness
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collision energy
kinetic energy absorbed during the collision
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rebound energy
kinetic energy released during the rebound
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coefficient of restitution
coefficient of restitution = rebound speed of ball / collision speed of the ball
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vibrational node
points near each end of the bat that do not move when the bat vibrates
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elastic collisions
bounces so perfect that all of the collision energy is stored and returned as rebound energy
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inelastic collisions
collisions that fail to return some of the collision energy as rebound energy
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centripetal acceleration
- "center-seeking"
- brings toward the center
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Nicolaus Copernicus
- 1473-1543
- Heliocentric theory
- start of modern astronomy
- delayed publication of his book till the year of his death
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Galileo Galilei
- 1564-1642
- championed heliocentric universe by observation
- telescope observations
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Johannes Kepler
- laws of planetary motion
- used data of Tyco Brahe as postulate motion of planets
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Kepler's laws
- 1. planet orbits = ellipses
- 2. area swept fro the sun to a planet is constant in time (conservation of angular momentum, speeds up closer to foci)
- 3. the bigger the orbit, the longer it takes the planet to go around its orbit
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geosynchronous orbit
- at 35,900km above the earth's surface
- orbits the earth every 24 hours, stays at same place above the earth
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