Stuck — 399 discussions

Homework Statement "A small radio transmitter broadcasts in a 25 mile radius. If you drive along a straight line from a city 30 miles north of the transmitter to a second city 33 miles east of the transmitter, during how much of the drive will you pick up a signal from the transmitter?"Homework...

Homework Statement Hello I need some advice on how to figure out Part F of the following problem. I was able to find the correct answer but in a very illogical way. I was wondering if I could get some help understanding the lorentz transformations necessary. Here is the full problem, I have...

Homework Statement For a volume charge, ##\textbf{E}(\textbf{r}) = \frac{1}{4\pi\epsilon_0}\int_{all space}\frac{\hat{\gamma}}{\gamma^2}\rho(r')d\tau'## and I am trying to get the divergence of it. Homework Equations The book says ##\nabla\cdot\textbf{E} = \frac{1}{4\pi\epsilon_0}\int_{all...

I am new to using MOSFET transistors as load switches. Here, I am trying to trigger the P-channel MOSFET to run a current through the 180 ohm resistor. I can not figure out what I am doing wrong. It is supposed to turn on for a small moment (at the zero-crossing moment of the AC phase), then...

Homework Statement Using the principle of mathematical induction, prove that for all n>=10, 2^n>n^3 Homework Equations 2^(n+1) = 2(2^n) (n+1)^3 = n^3 + 3n^2 + 3n +1 The Attempt at a Solution i) (Base case) Statement is true for n=10 ii)(inductive step) Suppose 2^n > n^3 for some integer >=...

this is a nother problem from my study guide. it starts with a statement A) a/b B) 10/11 based on this information you have to choose an answer: a)quantity A is greater b)quantity B is greater c)the two are equal d)the relationship can not be...

Homework Statement The question asks to calculate the jerk of an object (both its direction and magnitude) in uniform circular motion. Homework Equations j=d(a)/dt The Attempt at a Solution I know that the direction is opposite the velocity vector (I did this by drawing a circle and taking a...

Homework Statement Find the Inverse laplace transform of: http://www4c.wolframalpha.com/Calculate/MSP/MSP14541hg721e74730d4fb00004644i96f59549h1d?MSPStoreType=image/gif&s=30&w=201.&h=40. Result...

Homework Statement [/B] I'm working through a problem in Abott's Understanding Analysis, second edition, the statement of the problem being: "Fix a member n of the natural numbers and let An be the algebraic numbers obtained as roots of polynomials with integer coefficients that have degree n...

Hi... any idea on how to calculate force needed to pull up something stuck on the ground? ex: Boot stuck on mud person sinking on quicksand or car sinking in water

Hey guys ! :) Last week I went on a Trip to this place 3500 ft above sea level, as I was walking my rubber boots got stuck on a big pile of mud (almost 30 to 40 cm) of my boots. I managed to take one out but the other was so stuck I had to play the natives to help me get it out. So my question...

Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 3.1 m/s2 for 3.7 seconds. It then continues at a constant speed for 12.5 seconds, before applying the brakes such that the car’s speed decreases...

"A cricket ball moving at 4m/s south, is hit over square leg which is due west at 3m/s, what is the change in velocity?" The change in velocity ΔV= V-U (where V= final velocity and U= initial velocity) The way I was shown is to add negative U to V, which would give us the same triangle and...

Homework Statement A ball of mass M and radius R can rotate round an axis through it's center. a bullet of mass m travels with speed v, hits the ball near the surface and gets stuck in it. What's their angular velocity after the collision. Homework Equations Moment of inertia of a ball round...

Hello, here is a couple of example problems I'm not sure how to do, if someone could please explain how to do it I would greatly appreciate it! Subtraction: "A river flows at 0.8 m/s. If a boat moves across the water at 2m/s at what angle should it point so that it moves straight across the...

I've been working through some dirac notation and I'm stuck... Here's where I'm at: I understand that an expectation value: <x> = ∫ ψ* x ψ dx = <ψ|xψ> = <ψ|x|ψ> Also, we can say H|ψ> = E|ψ> where E is an eigenvalue of the operator H and |ψ> represents a state your acting on. I get that you can...

Given polynomial P(a,b,c,d,e,f...n) = (a^0)(b^1)(c^2)...(n^n) show that the sum of P(a,b,c,d,e,f...x) when acted upon by the symmetric group of order n and each time multipled by the sgn function (1 if even and -1 if odd); that this sum is equal to the vandermonde determinant of these...

The problem statement ln(x) = 5 -x Solve for x. The attempt at a solution ln x = 5 - x \\ e^{ln x} = e^{5 - x} \\ e^{ln x} = \frac{e^5}{e^x} \\ x e^x = e^5 Here is the place where I get stuck.

I'm just here to rant a little...I'm an undergrad and working on a physics research project with a theoretical physics professor. I respect and trust my advisor's judgment with everything and would not considering trying to work with another professor at my university. She told me beforehand...

So I am a High school student from Australia and I'm slow when it comes to mathematics (2 Unit) and I'm not doing to well in the tests, I'm getting around 50%. I was wondering if I should drop to general Maths, which I know isn't recommended for University Physics. The recommended is instead...

Homework Statement I have been trying to solve this problem all day, I have used up 3 pages and to no avail. I don't think i should try and change the bases because of the way the book is set up changing bases is not until the next chapter. So I want to try and get it out without changing...

Hello, I am stuck between two majors to study in college, Computer Engineering and Aerospace Engineering. About me: I am going to be a senior next year and I am going to be taking high level ap calculus and ap physics. I am a very creative person and am very good at the arts and industrial...

Homework Statement I am trying to show that ##a(x)[u(x),D^{3}]=-au_{xxx}-3au_{xx}D-3au_{x}D^{2}##, where ##D=d/dx##, ##D^{2}=d^{2}/dx^{2} ## etc.Homework Equations [/B] I have the known results : ##[D,u]=u_{x}## ##[D^{2},u]=u_{xx}+2u_{x}D## The property: ##[A,BC]=[A,B]C+B[A,C] ##*The...

i have a question if i may i have a flyback I am trying to turn into a power source but all the tutorials show a flyback that is way different than mine there's only has one wire out of the top mine has three one from the top and two on the side labeled screen and focus i really need a high...

Mentor note: fixed formulas so they get displayed properly If we take the K-G eqn and the following term for the wave function $$( \partial^2 + \frac{m^{2}c^{2}}{\hbar^{2}})\Psi =0 \\\\\Psi = Re^{-i\omega t + i k_{i}x_{i}}$$We worked through to this ##\hbar \omega = \pm \sqrt{\hbar^{2}...

Im 17 senior year high school in india. I want to study applied math and business for undergraduate in university. Is it possible doing both at the same time? I want to do my undergrads from us most probably. I've also taken physics,chem, math in high school as my main subjects. I haven't taken...

Hi. This is not a homework assignment. I am working to get an extrema on a graph that involves a bunch of functions and got stuck on one step: How to get the derivative of: \frac{dy}{dn} = \frac{nc(a+b)}{nc+a} I can't get "n" in a place where I recognize how to get the derivative of it. I...

Homework Statement In what directions at the point (2, 0) does the function f(x, y) = xy have rate of change -1?D_{u}(f)(a,b) = \bigtriangledown f(a,b)\cdot (u_{1}, u_{2}) f(x,y) = xy (a,b) = (2,0). The Attempt at a Solution \frac{\partial f}{\partial x} = y \frac{\partial f}{\partial y} =...

Hello. I'm going through Ray D'Inverno's "Introducing Einstein's Relativity" and I'm stuck at a certain point and can't move forward. It deals with tensors, I'm stuck at the transformation matrix and the problem is, I can't figure out what the key equation (5.7) actually means. There is a...

Rg. Without air resistance, show the maximum height snow can reach is h_max=R+v^2/(2g)+gR^2/(2v^2) Solve using conservation of energy How do I start this problem? I assume all the initial kinetic energy ((mv^2)/2) from the spinning of the tire is translated to the gravitational potential energy...

Somehow I managed to get the Boomtown Rats - I Don't Like Mondays, stuck in my head

(like the wavefront that is photographed when it travels through air)

I'm stuck on deriving the follow. Context: FRW Metric, dust dominated universe, use of conservation of energy-momentum tensor. I'll now state all the equations I can see are relevant. (But just in case the source is http://arxiv.org/pdf/gr-qc/9712019.pdf and it's eq 8.43). ## \frac{d}{dt}(\rho...

Hi! Long story short, I studied Civil E (Structural and Geotechnical), which it turns out I don't like. On the other hand, I found over the years I really like Electrical E. I don't have neither time nor money to go back to school, but I'm determined to learn some of it on my own. Because I...

Homework Statement Integrating ##^{\frac{\pi}{2}}\int_{\frac{-\pi}{2}}(1-u^{2})^\frac{1}{2}u_{x}dx##, and using the result : ##\int(1-u^{2})^{\frac{1}{2}}=\frac{1}{2}u(1-u^{2})^{\frac{1}{2}}+\frac{1}{2}arcsin(u)## Homework Equations I'm pretty sure it is just the integral itself were I am...

I have been tearing my hair out for a while over a step in the proof of the relation pV^{\gamma}=constant. The textbook has assumed that we are dealing with an ideal gas undergoing an adiabatic process. Therefore dQ=0 and we get $$C_vdT + (c_p-c_V)\left(\frac{\partial T}{\partial...

So I started with limits and everything went well, and then into derivatives, and a problem started. First I know how to find the derivative of basic things using like ( limit definition of derivative) or (rules for derivatives) or ( product rule/ quotient rule/ chain rule)... My problem...

Let H subgroup in G. Prove H is normal in G iff for all g in G and for all h in H, there exists an h1 and h2 in H such that hg=gh1 and gh=h2g.Completely lost on this. All I know for normal is that gH=Hg. Where else do I go from here? Help a brother out! Thanks :)

Homework Statement I've been attempting this problem all day now. My current submissions are 10.6N and I keep getting 7.04N every time I retry it but this is also wrong. Can somebody please help me out so I can figure out what I'm doing wrong? Thanks for any help in advanced! The 3.35kg collar...

Homework Statement Please see the attached file. Homework EquationsThe Attempt at a Solution If my math is right so far, I am basically stuck as to what to do with the E(t) term. [/B]

A question I am working on $$\frac{3}{x}+\frac{2}{y}=14$$ (1) $$\frac{5}{x}-\frac{3}{y}=-2$$ (2) let $$\frac{1}{x}=a$$ let $$\frac{1}{y}=b$$ $$\therefore3a+2b=14$$ (3) (x5) $$5a-3b=-2$$ (4) (x3) $$=15a+10b=70$$ (5) $$15a-9b=-6$$ (6) (5)-(6) 15a cancels out. Leaving 19b=76 $$b=\frac{76}{19}$$...

Homework Statement What would be the effect of calculated value if: a. Jockey weight is in error by 1 g? b. Distance from vane center to pivot point is in error by 1 mm? c. diameter of nozzle 0.1mm different from actual nozzle diameter. Homework EquationsThe Attempt at a Solution as the error...

A toy plane with a mass of 1.04 kg is tied to a string and made to travel at a speed of 23 m/s in a horizontal circle with a 17-m radius. The person holding the string pulls the plane in, increasing the tension in the string, increasing the speed of the plane and decreasing the radius of the...

I was studying on the differential equations and I got stuck now at an integral after all I've transformed the Bernoulli Differential Equation into First-order Linear ODE. Where I'm stuck on: \int\frac{e^{2x}}{x^2}\,dx=? And the Bernoulli Differential Equation is: xy'+y-y^2e^(2x)=0,\ \ y(1)=2\...

I don't know if this can be calculated. I have tried for hours and days to isolate/calculate the radius and angles of the circle in order to be able to calculate length 1. I have tried using cos/sin-relation formulas and triangle formas - but Iam stuck. Any hints would be greatly appreciated...

Homework Statement Question:[/B] ____________________________________________________________________________________ And the answer in the solution manual: Homework Equations Trig sub? a^2/x^2 = tan(θ) I'm thinking x>>a would affect this majorly and I'm not seeing how. The Attempt at a...

An infinitely long solid insulating cylinder of radius a = 5.2 cm is positioned with its symmetry axis along the z-axis as shown. The cylinder is uniformly charged with a charge density ρ = 23 μC/m3. Concentric with the cylinder is a cylindrical conducting shell of inner radius b = 14.2 cm, and...

Homework Statement Hey. I am taking my first Real Analysis course at the undergraduate level and am not really sure where to start on a problem. I do have some ideas. I am not asking anyone to solve it for me, but I do need an idea where to start. Show that |f(x)-f(x0)|<|x-x0| if...

One of the founding principals of our company approached me last week asking me to come have a chat with him in his office. (I had never had any interaction with him before this point) Anyways, he explained how he needed someone to rewrite the documentation for one of our manuals and asked...

I can't tell you how many attempts I've had at this. I must be following the current wrong, or something... PLEASE HELP.. this is an example from the chapter! I feel very stupid...