The key discovery about Cepheid variable stars that led in the 1920s to the resolution of the question of whether spiral "nebulae" were separate and distant galaxies or part of the Milky Way Galaxy was the direct relationship between the pulsation period and the absolute brightness or luminosity of the Cepheid variables. A measurement of brightness of a variable star could then be used to determine the distance to the "nebula" containing it.
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Physics, 21.06.2019 19:50
An object is dropped from a tower, 400 ft above the ground. the object's height above ground t seconds after the fall is s(t)equals400 minus 16 t squared. determine the velocity and acceleration of the object the moment it reaches the ground. the velocity of the object the moment it reaches the ground is nothing ft/s.
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Physics, 22.06.2019 10:30
Apulley with mass mp and a radius rp is attached to the ceiling, in a gravity field of 9.81 m/s2 and rotates with no friction about its pivot.
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Physics, 22.06.2019 10:30
Astone weighing 1.5 kilograms is resting on a rock at a height of 20 meters above the ground. the stone rolls down 10 meters and comes to rest on a patch of moss. the gravitational potential energy of the stone on the moss is joules.
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Physics, 22.06.2019 12:00
Explain what happens at the saturation point when adding salt to water at room temperature.
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The key discovery about Cepheid variable stars that led in the 1920s to the resolution of the questi...
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