Physics, 10.07.2019 21:40 tamaraquirozmorales
An important quantity in theories of the formation of galaxies is the jeans length. in this question, you will determine the jeans length at the time. suppose we have an infinite medium of temperature t and density pm now let the density increase slightly in one region the increased gravitational force will tend to compress the region. however this force will be countered by increased pressure, p - pktim, where k is the boltzmann constant and m is the mean mass of the particles. (a) how does temperature scale as the universe expands? how does density scale as the universe expands? suppose that t-3k at the present time, and that the present density is p-9x1030g. cm. what was the density at the time of recombination when t-3000k? (b) we can now use hydrostatic equilibrium to determine whether a small region of diameter l will collapse. the weight of a column of material of unit area and height l is roughly gm ,where m is the mass of material in the region l. show that the smallest l2 kt region which will collapse is given by l , where we can take m to be the mgp mass of the hydrogen atom, 1.67 x 102g. explain any assumptions you make. (c) what is the jeans length at recombination? find the corresponding jeans mass. what sort of object might this be in the universe today?
Answers: 1
Physics, 21.06.2019 23:20
In the sport of parasailing, a person is attached to a rope being pulled by a boat while hanging from a parachute-like sail. a rider is towed at a constant speed by a rope that is at an angle of 15 ∘ from horizontal. the tension in the rope is 1900 n. the force of the sail on the rider is 30∘ from horizontal. what is the weight of the rider? express your answer with the appropriate units.
Answers: 1
Physics, 22.06.2019 04:00
Ametal ball with a mass of 0.028 kg is dropped from rest at a height of 1.0 meters above the ground. assuming the energy in the ball is conserved, how much kinetic energy will the ball have when it is 0.5 meters above the ground?
Answers: 1
Physics, 22.06.2019 15:30
Ametal ring 4.20 cm in diameter is placed between the north and south poles of large magnets with the plane of its area perpendicular to the magnetic field. these magnets produce an initial uniform field of 1.12 t between them but are gradually pulled apart, causing this field to remain uniform but decrease steadily at 0.240 t/s . (a) what is the magnitude of the electric field induced in the ring? (b) in which direction (clockwise or counterclockwise) does the current flow as viewed by someone on the south pole of the magnet?
Answers: 2
Physics, 22.06.2019 16:30
Write a polynomial function with the given zeros x= -1,0,2show your work
Answers: 3
An important quantity in theories of the formation of galaxies is the jeans length. in this question...
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