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Definitions |
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On earth acceleration
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g~10m/s^2: speed increases 10m/s with each second falling
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real life examples of doppler
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doppler radar for weather
airplane radar system
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mass
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amount of matter in an object
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weight
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the force that acts upon an object
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why are astronauts weightless in space
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there is gravity in space, weightlessness is due to constant state of free fall
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How do we describe motion
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speed, velocity, & acceleration
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Doppler shifts
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redshift(longer wavelengths):the source is moving away from the observer
blue shift(shorter wavelengths): the source is moving toward the observer
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The suns spectrum
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hot dense core surrounded by a low density outer atmosphere
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Doppler effect used by astronomers to
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learn the radial (along the line of sight) motions of stars, other astronomical objects
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along the line of sight
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means the doppler effect happens only if the object which emitting light is moving toward you or away from you. and object moving side 2 side or perpendicular relative to your line of sight will not experience the doppler effect
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Newtons 2nd law of motion
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force= mass x acceleration
the bigger the force, the greater the resulting acceleration on a given mass
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speed
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rate at which objects move
speed =distance/time units of (m/s) ex: 10m/s
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acceleration
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any change in velocity units of speed/time (m/s^2)
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chemical fingerprints (continued)
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each type of atom has a unique spectral fingerprint
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stars temperature
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peak wavelength of the spectral curve
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velocity
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speed and direction
ex: 10 m/s due east
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stars motion
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doppler shift
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momentum
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mass x velocity
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what can we learn by analyzing starlight?
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stars temperature and chemical composition. a stars motion
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Chemical fingerprints
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downward transitions produce a unique pattern of emission lines
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applying a force
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acceleration (change in velocity)-> change in momentum
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angular momentum
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rotational momentum of spinning or orbiting object is know as angular momentum
angular momentum = mass x velocity x radius
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force
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causes change in momentum producing acceleration
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Doppler effect wavelengths
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When something that is giving off light moves
toward or away from you, the wavelength of the
emitted light is changed or shifted.
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is there a difference between mass and weight?
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yes
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all star produce
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absorption spectra
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energy level transitions
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the only allowed changes in energy are those corresponding to a transition between energy levels
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all falling objects
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accelerate at the same rate on earth (not counting friction of air resistance)
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Newtons 3rd law of motion
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For every force, there is always an equal and opposite reaction force
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doppler effect
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the change in wavelength due to the relative motion between the source and the observer along the line of sight
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Acceleration of gravity
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(g) gravity is the same for all falling objects regardless of their mass
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the amount of shift
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is proportional to the relative velocity
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Newtons law of universal gravitation
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the force of gravitational attraction exerted by one object on another depends on
mass of the 1st object (M)
mass of the 2nd object (m)
distance between the objects (r)
F=GMm/r^2
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stars chemical composition
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dips in the spectral curve or the lines in the absorption spectrum
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Newtons 1st law of motion
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object moves at constant velocity unless a net force acts to change its speed or direction
ex) scooter will coast with a same speed until you brake or kick
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Universal law of Gravitation
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1. Every mass attracts every other mass.
2. Attraction is directly proportional to the product of their masses.
3.Attraction is inversely proportional to the square of the distance between their centers.
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