John Dalton. Modern Atomic Theory (John Dalton) Experiments with gases that first became possible at the turn of the nineteenth century led John Dalton in 1803 to propose a modern theory of the atom based on the following assumptions. 1. Matter is made up of atoms that are indivisible and indestructible.
The constant angular acceleration (in rad/s2) of the centrifuge is 194.02 rad/s².
<h3> Constant angular acceleration</h3>
Apply the following kinematic equation;
ωf² = ωi² - 2αθ
where;
- ωf is the final angular velocity when the centrifuge stops = 0
- ωi is the initial angular velocity
- θ is angular displacement
- α is angular acceleration
ωi = 3400 rev/min x 2π rad/rev x 1 min/60s = 356.05 rad/s
θ = 52 rev x 2π rad/rev = 326.7 rad
0 = ωi² - 2αθ
α = ωi²/2θ
α = ( 356.05²) / (2 x 326.7)
α = 194.02 rad/s²
Thus, the constant angular acceleration (in rad/s2) of the centrifuge is 194.02 rad/s².
Learn more about angular acceleration here: brainly.com/question/25129606
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Answer:
The Ptolemaic model of the universe <u><em>A) explained and predicted the motions of the planets with deferents and epicycles.</em></u>
Explanation:
Ptolemy of Alexandria built an explanation of the observed movements of the planets that remained in force for thirteen centuries. Ptolemy proposed a model of the Universe with the Earth in the center. In the model, the Earth remains stationary while the planets, the Moon and the Sun describe complicated orbits around it. In other words, Ptolemy devised a system in which he used epicycles, deferential and eccentric, and it was necessary to introduce an equating point to reproduce planetary movements. He proposed that:
a) Each planet revolves with constant velocity around a circle called an epicycle.
b) The center of the epicycle is located and moves with constant velocity around another circle called deferential.
c) The center of the deferent is located at a moving point, which travels with constant speed describing another circumference called eccentric.
d) The center of the eccentric coincides with the center of the Universe.
e) Since the Earth is not located in the center of the Universe, but very close to it, it was necessary to introduce an equating point, which is not on Earth, and from which you can see the planet move with constant speed.
However, Ptolemy put forward this geometric theory to explain mathematically the movements and failed to adjust any system of cycles, epicycles and eccentrics that accurately represented the observed movements of the planets.
Finally, <u><em>The Ptolemaic model of the universe A) explained and predicted the motions of the planets with deferents and epicycles.</em></u>
Answer:
Explanation:
Suppose initially the plane was horizontal and light was reflected back at some angle θ from the normal .
Now the reflecting surface is twisted so that is becomes inclined at angle alpha .
The reflected light will be deviated from its original direction by angle
2 x alpha .
Similarly when the reflecting surface is further twisted so that it becomes inclined at angle beta then again the reflected beam will deviated by angle
2 x beta
Hence angle between these two reflected beam
= 2 beta - 2 alpha
= 2 ( β - α )
So, angular separation between the rays reflected from the two surfaces
= 2 ( β - α ) .
