Question 29.6 on p. 982 of the textbook university physics 13th edition states that a magnet would reach terminal velocity even if there is no air resistance. How would air resistance change the situation? Is it significant?

03.2 A boat must cross a 190-m-wide river and arrive at a point 30 m upstream from where it starts (see figure). To do so, the pilot must head the boat at an angle ?         = 40

Draw the following circuits:

a. (1 pt) What is the purpose of a rectifier circuit?

b. (2 pts) Half

I am interested in examples of crackpots coming up with correct results in physics.

Why do mainstream physicists look down so much upon "crackpots"?

What basic law of Physics tells us that a laser cannot produce 100% monochromatic light?

Explain the origin of Transverse Electromagnetic Modes (TEM modes) in a commercial laser. Use words and diagrams as necessary.

Explain the concept of collisional broadening in a gas laser

The Kwik-Freez Appliance Co wants you to design a food freezer that will keep the freezing compartment at -5.00?C and will operate in a room at 20.0?C. The freezer is to make 5.80kg of ice at 0 ?C, starting with water at 20.0?C.

a) Find the least possible amount of electrical energy needed to make this ice

b) Find the smallest possible amount of heat expelled into the room.

At launch a rocket accelerates upward at a=2g. After 12 seconds the rocket runs out of fuel and enters freefall.

a.) Determine the rocket's maximum height.

b.) How long after take off does the rocket crash to the ground?

Perturbation theory presumes we have a valid family of models over some continuous (infinitely differentiable, in fact) range for some parameters, i.e. coupling constants. We have some special values for the coupling constants characterizing the unperturbed model, which presumably, is relatively easy to solve. We also assume the family of models transform smoothly under the coupling constants. Then, we perform a Taylor series analysis.

But what if the landscape of valid quantum gravity models is discrete? Even though superstring theory admits a dilaton modulus over 10 uncompactified dimensions, what about the landscape of models we get after compactifying 6 spatial dimensions with nonzero fluxes and some branes, and maybe some orbifolding? We still have moduli when supersymmetry remains unbroken, but what about the metastable states where SUSY is broken? What is the Taylor series of a Dirac delta function?

What about perturbation theory from the perspective of path integrals? With path integrals, the Wheeler-DeWitt constraint shows up in a different guise as a projection operator. We start off with some wavefunctionals, and then take the functional integral over some finite time interval T. In the limit as T goes to infinity, we are left with a projection operator singling out WDW solutions. But what happens when we interchange the order in which we take the limit of the coupling constant going to zero, and T going to infinity? If the spectrum of the Hamiltonian constraint is discrete, and varies with the coupling constant, such an interchange won't be valid! This is a fancy way of saying for most choices of coupling constants, the projection operator is zero.

There has been some heated debate as to whether the laws of physics allow for traversable wormholes. Some physicists claim we require exotic matter to construct wormholes, but then others counter the Casimir effect with ordinary matter is sufficient. But these same physicists seldom come up with an explicit solution or state of ordinary matter keeping the throat of a wormhole open via the Casimir effect. Yet others claim with extra dimensions, a Gauss-Bonnet interaction is sufficient to keep the wormhole throat open, but opposing physicists claim such a term can't arise from string theory.

So, my question is, do traversable wormholes exist as solutions to string theory?

Am I correct it remembering that unless a pulsars beams plane faces earth we can not detect them. And that similarly inbetween the pulses we can't see them either?

If so how does this differ from dark matter? Isn't it possible that there are a lot more pulsars that we just can't see them because they are pointing the wrong way.

I'm trying to solve a problem where I have an object resting on an inclined plane, with the angle of the plan being alpha, and the weight being w. I'm having trouble figuring out how I can calculate the component of the weight parallel to the plane. I also want to find out the weight component perpendicular to the plane.

I don't want an outright answer, more of an explanation to help me understand. Thanks!

Three charged marbles are glued to a nonconducting surface and are placed in the diagram as shown. The charges of each marble are q₁ = 5.95

A dipole lies on the y axis and consists of an electron at y1 = 0.50nm and a proton at y2 = -0.50nm .

Part A

Find the electric field midway between the two charges.

Express your answer using two significant figures. Enter your answers numerically separated by a comma.

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Part B

Find the electric field at the point x = -1.5nm , y = 0.

Express your answer using two significant figures. Enter your answers numerically separated by a comma.

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Part C

Find the electric field at the point x = -26nm , y = 0.

Express your answer using two significant figures. Enter your answers numerically separated by a comma.

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