A rock is thrown at a window that is located at a height h = 36.33 m above the ground. The rock is thrown at an angle of θ above horizontal. The rock is thrown at time 0 seconds from a height of hi = 2.00 m above the ground with an initial speed of v0 and experiences no appreciable air resistance. After t = 2.0 seconds, let the velocity of the rock be v =(15.00 i + 6.38 j ̂)m/s, where x-axis is a horizontal axis and y-axis is vertical and positive upward.
Write the expression for the y-component of the initial velocity in terms of the time t, the velocity at time t (vy), and the gravitation acceleration g.
Find the initial speed in m/s.
Find the initial angle with the horizontal in degrees.
If the rock strikes the window on its downward trajectory, calculate the time (call it tw) measured in seconds at which it will hit the window.
Calculate the horizontal distance in meters from where it was initially thrown to the window.
What was the maximum height (measured from the ground in meters) the rock has reached?
In: Physics
In: Physics
1-why the mobility of electron is higher than hole?
2-why effective mass of hole is greater than electron?
3-why are holes heavier than electrons?
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i am doing an internship in the physics department i
was lucky enough to actually get this internship as ive just
finished my first year. the problem is i have a very professional
professor he is so so smart so whenever he explains something to me
i just don't understand it, i feel like we have so much mis
understanding between me and him. The way he asks me to do things
seems so vague to me but so obvious to him so when i come back to
him and say ive done this and that he'll be like this is not what i
asked you to do or your not listening he makes me feel that im
stupid, but im not.
what can i do to improve? how can i deal with this situation? it's humiliating sometimes especially that im here to learn not to like do actal work quickly.
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could you take pictures of a good presentation in power point that illustrates how you present data and do analysis for this data especially if it was graphs?
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In: Physics
(Figure 1) shows an acceleration-versus-force graph for three objects pulled by rubber bands. The mass of object 2 is 0.30 kg . The graph reads: object 1 a=5 and force of 2 rubber bands. Object 2 a= 5 and force of 5 rubber bands. Object 3 a=2.5 with force of 6 rubber bands. What is the mass of objects 1 and 3?
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In: Physics
A spring with spring constant 14 N/m hangs from the ceiling. A ball is attached to the spring and allowed to come to rest. It is then pulled down 7.0 cm and released. The ball makes 29 oscillations in 25 s seconds.
a) What is its the mass of the ball?
b) What is its maximum speed?
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When measuring signal from a radio source, we receive signals from many electrons emitting arbitrary sine waves. Why do we receive the signal from lots of electrons and why do they emit signals of different frequencies, phases and amplitudes?
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A lightning bolt strikes one end of a steel lightning rod, producing a 14700-A current burst that lasts for 63 μs. The rod is 2.2 mm long and 2.3 cm in diameter, and its other end is connected to the ground by 30 mm of 7.8-mm-diameter copper wire.
A.) Find the potential difference between the top of the steel rod and the lower end of the copper wire during the current burst.
B.) Find the total energy deposited in the rod and wire by the current burst.
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Unpolarized light is incident on a waveguide made of a dense glass (index of refraction n2 ) that is coated with a layer of quartz (index of refraction n3). The waveguide is immersed in a medium with index of refraction n1.
Assume the wavelength of of the incident light is 500 nm, n1= 1.00, n2= 1.80 and n3 = 1.45.
A) The speed of light in the dense glass is most nearly ["2.25", "1.875", "2.00", "1.50", "3.00", "1.67"] x 108 m/s
B) The critical angle for total internal reflection off the dense glass / quartz surface is ["53.7", "63.3", "47.3", "69.0", "56.3"]
C) For the beam reflecting off the air/dense glass surface to be completely polarized, θ1 would have to be ["58.0", "63.4", "56.3", "47.3", "60.9"]
D) If the beam reflecting off the air/dense glass surface is completely polarized, the polarization would be ["Both parallel and perpendicular to the surface", "parallel to the surface", "perpendicular to the surface"]
E) If the angle of incidence θ1 = 40 degrees, θ2= ["20.9", "25.4", "13.2", "22.5", "28.6"] and θ3 = ["64.6", "67.5", "69.1", "90", "61.4"]
F) Will the light totally internally reflect and stay in the dense glass or refract into the quartz? ["It will totally reflect", "It will only refract", "", "It will both reflect and refract"]
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How to solve this question?
Take specific gas constant for carbon dioxide R = 0.189 kJ/kg K
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A) What is the average number density of particles inside the brown dwarf, given that the average mass per particle is about 10^−24 gram? (Hint: The volume of a sphere of radius r is equal to 4πr3/3 .) (A brown dwarf with a mass of 0.04 MSun and a radius of 0.1 RSun.)
B) What is the approximate temperature necessary for gas pressure to balance gravity within the brown dwarf, given the average particle density from part A?
C) How does that temperature compare with the 1×10^7K temperature needed to sustain hydrogen fusion?
D) Explain how conditions inside the brown dwarf would change if you raised its mass to 0.12 MSun.
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