A thin film of MGF2 has a refractive index of n = 1.38 and it is deposited on glass as an anti-reflective layer of light with a wavelength of 580nm which falls in the normal direction towards the film. What wavelength is minimally reflected when the light falls at 45 ° towards the film?
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3) A 2 kg block is sliding at an initial speed of 10 m/s across a surface, encountering a constant friction force of 7 N. How much work is done on the block after it slides 22 cm?
Answer:
Hint: Does the block gain or lose energy during
this process? What sign does this imply for the work done on
it?
4) How fast is the block moving after sliding 22 cm?
Answer:
Hint: You can treat the block like a simple
particle. What kind of energy does it have and how is this affected
by the work done on it?
5) What's the total distance the block travels before coming to
rest?
Correct, computer gets: 14.29 m
6) What is the average power of friction on the block over the time
it takes the block to come to rest?
Answer:
7) What was the instantaneous power of friction on the block after
it slid the first 22 cm?
Answer
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Im stuck on questions (
Questions 2a-c (refer to a 0.250 kg pendulum, and then answer 2a-d)
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An object suspended from a spring with a spring constant of 2.56 N/m vibrates with a frequency of 0.148 Hz.
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f=½(pi) x sqroot(k/m) 0.148Hz=½(pi) x sqroot(2.56N/m / m) 0.148 x 2(pi)= sqroot(2.56)/m 0.93 = sqroot(2.56Hz/m) 0.93^2=sqroot(2.56Hz/m) m=2.66/0.93^2 = 2.96kg The mass is 2.96kg |
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a=-wx sqroot(k/m)=sqroot(2.56/2.96=0.93rad/s^2) a=-0.93x(-0.12)=0.112m/s^2 The acceleration is 0.112m/s^2 |
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Questions 2a-c refer to a 0.250 kg pendulum.
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A match 5 cm long is placed 20 cm in front of a concave mirror whose focal length is 50 cm. Find the location, size, and nature of the image.
)
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Identify a few contemporary societal facets that are affected so heavily by innovation in engineering and the sciences.
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3. In ion mobility spectrometer, the ions are accelerated under a constant electric field in a cylindrical tube and the time of flight of the ions in this tube is measured. The ions are detected by using a sensor at the end of the tube. a) What type of sensor can be used to detect the ions? b) The experiment is performed at high frequencies to be able to decrease the effect of the noise. What type of noises can be present in this experiment?c) During the experiment, many devices are used together. What type of grounding can be used for this experimental setup to be able to prevent floating grounds and crosstalks? d)
| t(s) x 10^-6 | ? (cm^2 x V^-1 x s^-1 ) |
|---|---|
| 8.5 | 1100.0 |
| 7.0 | 1350.0 |
| 5.0 | 1600.0 |
| 3.5 | 1850.0 |
| 2.0 | 2100.0 |
The mobility of the ions is given as ? = ? ? 1 ? , where l, E and t are the length of the tube, the electric field strength and the time of flight, respectively. The data given in the table belongs to a specific type of spectrometer. By plotting this data, find the required length of the tube for an electric field strength of 10^4 V/cm.
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A.Please answer these questions:
1) For which n does the complete graph Kn have an Eulerian circuit?
2) For which n does the complete graph Kn have a Hamiltonian Cycle?
3）For which r, s does the complete bipartite graph Kr,s have an Eulerian circuit?
4） For which r, s does the complete bipartite graph Kr,s have a Hamiltonian Cycle?
5）Find a graph that has an Eulerian circuit but no Hamiltonian Cycle?
6）Find a graph that has a Hamiltonian Cycle but no Eulerian circuit?
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. It is often said that “water seeks its level.” Explain
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A bumper car with mass m1 = 122 kg is moving to the right with a velocity of v1 = 4.5 m/s. A second bumper car with mass m2 = 2m1 = 244 kg is at rest. The two have an elastic collision and the first bumper car rebounds backwards at a speed that is 1/3 of its original speed (1.5 m/s). Assume the surface is frictionless.
1) What is the change in momentum of bumper car 1? (let the positive direction be to the right)
2) What is the change in momentum of BOTH bumper cars combined?
3) What is the change in momentum of bumper car 2?
4) What is the final velocity of car 2?
5) What is the change in energy of bumper car 1?
6) What is the change in energy of BOTH bumper cars combined?
7) What is the change in energy of bumper car 2?
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7.15 Channel equalization. We suppose that u1, . . . , um is a signal (time series) that is trans- mitted (for example by radio). A receiver receives the signal y = c ∗ u, where the n-vector c is called the channel impulse response. In most applications n is small, e.g., under 10, and m is much larger. An equalizer is a k-vector h that satisfies h∗c ≈ e1, the first unit vector of length n + k − 1. The receiver equalizes the received signal y by convolving it with the equalizer to obtain z = h ∗ y.
(a) How are z (the equalized received signal) and u (the original transmitted signal) related? Hint. Recall that h∗(c∗u) = (h∗c)∗u.
(b) Numerical example. Generate a signal u of length m = 50, with each entry a random value that is either −1 or +1. Plot u and y = c ∗ u, with c = (1,0.7,−0.3). Also plot the equalized signal z = h ∗ y, with
h = (0.9, −0.5, 0.5, −0.4, 0.3, −0.3, 0.2, −0.1).
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propagate errors for magnitude and theta.
magnitude(aka R) = sqrt(Rx2+Ry2)
tetha = arctan(Ry/Rx)
unclear on how to get the equation delta R and delta theta.
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In an insulating box, there is a 140.0g block of lead whose temperature is 100K and a 70.0g block of tungsten whose temperature is 300K. (a) What is the equilibrium temperature of the two-block system? (b) What is the change in the internal energy of the system between the initial and the equilibrium state? (c) What is the change in the entropy of the system? (specific heat of tungsten: 0.0321cal/g · K, molar specific heat of tungsten: 24.8J/mol · K, specific heat of lead: 0.0305cal/g ·K, molar specific heat of lead: 26.5J/mol·K
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Question regarding moles:
So I'm having a hard time understanding the relationship between moles, molar mass, atomic/molecular mass, and unified atomic mass units.
Is molar mass and atomic/molecular mass the same thing? It seems like atomic/molecular mass is the sum of all the atomic masses in a substance. The units for atomic/molecular mass is unified atomic units and the units for molar mass is g/moles, so it seems like some type of conversion is happening. A Helium atom has an atomic mass of 4.00 u and a molar mass of 4.00 g/mol. So is 1 u = 1 g/mol? Doesn't that go against the idea that 1 u = 1.66 * 10^-27 kg? I can see that 1g/ mol = 10^-3 kg/mol, but how do you get rid of the mol part? Is it using the notion that in 1mole of gas there are 6.022 * 10^23 molecules to get that conversion because 1.66 * 10^-27 kg needs to equal 1 g/mol if 1g/mol = 1u?
Also physically, what is the difference between the mass of the substance and the atomic/molecular mass? If the substance is just the mass of everything it contains wouldn't that be the same thing as adding up all the molecules making that substance? I'm also assuming that the atomic/molecular mass is the actual mass of the atom or molecule itself, is that the case? Or is it like the mass of the nucleus of each atom (molecular mass would then be the sum of all the masses of all the nuclei). In that case, then the atomic mass doesnt include the mass of the electrons thus creating a difference between the actual mass of the substance and the atomic/molecular mass.
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Explanation of reasons why wireless electricity and energy harvesting could cut waste and reduce greenhouse gas emissions.
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What sort of exoplanets are the easiest target for direct imaging, and why?
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