Stuck — 399 discussions

I need to find a,b,c,d, and e. I know how to do these problems the normal way but now he's giving us the answer and asking us to work backwards. I'm stumped. I think I night need to use some sord of system of equations but I'm not sure what it would look like..

Hey guys! I'm stuck on a Laplace transform. Following is the problematic function: [cos(t)]^3 Seems simple, but I'm having issues doing the Laplace transform on odd trigonometric functions. When I use the half-angle formula, I get this, which I can't seem to solve: 1/2cos(t) +...

This assignment will give you practice with interactive programs, if/else statements, and methods that return values. Turn in a Java class named Grades in a file named Grades.java. You will be using a Scanner object for console input, so you will need to import java.util.*; into your program...

I'm a Junior, about to be a Senior, majoring in Physics at a California State University. I am terrified about my career prospects. I am a fairly good student (3.5 GPA) and really love physics. I've taken Quantum I, Modern Physics, Thermodynamics and a couple E&M classes and I have enjoyed...

A man hammers on a steel railway track. If you hear the sound through the track 5.0 seconds sooner than through the air, how far away is the man? *Steel - 5960m/s *Air - 346 m/s The question is simple but i can't get it Also please explain how to do a question like this in the answer.

Homework Statement A 1.2 g pebble is stuck in a tread of a 0.76 m diameter automobile tire, held in place by static friction that can be at most 3.6 N. The car starts from rest and gradually accelerates on a straight road. How fast is the car moving when the pebble flies out of the tire...

Homework Statement A 1.2 g pebble is stuck in a tread of a 0.76 m diameter automobile tire, held in place by static friction that can be at most 3.6 N. The car starts from rest and gradually accelerates on a straight road. How fast is the car moving when the pebble flies out of the tire tread...

http://imageshack.us/photo/my-images/585/circuitzzz.png/ i thought maybe i should ignore everything that is on the right side of the 3v and just focus on the left side. but this one is not looking too good for me. any ideas on this one??

When you do the 1st and 2nd derivatives of y2, you're supposed to get u' and u'' in your answer. My question is why can't you do it the way I've started to do it? Or, why are my answers for y2' and y2'' wrong? http://i.imgur.com/OarDiuW.jpg

I need to show the intervals where the wronskian is linearly independent and linearly dependent.. I don't know how to do that.. Here's what I have:

Q A cold yam is plaveedd in a hot oven. Newton's Law of Heating tells us that the difference between the oven's temperature and the yam's temperature decays exponentially with time. The yam's temperature is initially 0 deg F, the oven's temp is 300 deg F, and the temp difference decreases by 3%...

Homework Statement trying to write a program for school. the program is supposed to do the following: Write a program that takes an input value (for example, a number 5). The output should be sum of all numbers from 1 to the value input by the user (in this example, the output would be...

So I'm stuck resolving this integral... \int^{1}_{0} \sqrt{e^{2x} + 1} \, dx u=2x ; du=2dx \frac{1}{2}\int^{2}_{0} \sqrt{e^u + 1} \, du t=e^u+1 ; dt=e^u du \frac{1}{2}\int^{e^2 + 1}_{2} \frac{\sqrt{t}}{t-1} \, dt v=\sqrt{t} ; dv=\frac{1}{2\sqrt{t}} \int \frac{v^3}{v^2 -1} \, dv And here i...

Homework Statement Evaluate: ##\int -1 to 1 log((2-x)/(2+x)) dx## Homework Equations The Attempt at a Solution okay so normal attempt at integration won't work coz then we get log 1 what am i supposed to do i tried applying some general formulas of definite integral but i don't seem to...

I put it in std form, did the homogeneous test. it passed with degree 2. I substituted y=ux and dy=udx+xdu and now I'm stuck. it needs to be simplified somehow but I don't know if ux is one var or if it's u*x. Same goes for udx and xdu. Is it really u*dx+x*du? even assuming that is correct, it...

Homework Statement IntegrateHomework Equations I started with (2x^2+3)/(x^3-2x^2+3x) dxThe Attempt at a Solution Got dx/x + (x+2)/(x^2-2x+3) dx using the A/x + (Bx+C)/(x^2-2x+3) method. But I can't seem to solve (x+2)/(x^2-2x+3) dx Possible solutions are welcome.

Edit: Nevermind, figured it out. Thank you for readingOriginal problem: Find the interval of convergence \sum∞n=1 xn / n * √(n) * 3n Ratio Test, right? an+1/a I get to here and I can't figure out how to get rid of the ns: lim n→∞ abs(x/3)* [n*√(n) / (n+1)*√(n+1)] Solution, They break apart...

Homework Statement Prove that the following f'(x)=nx^{n-1} if f(x)=x^{n}Homework Equations Binomial theorem, definition of the derivative The Attempt at a Solution f'(x)=lim_{h\rightarrow0}\frac{f((x+h)^{n})-f(x)}{h} We need to expand the (x+h)^2 term now \sum^{n}_{k=0}{n\choose k}...

I'm reading some course notes for a physics class that contain the following step in a derivation: \phi(\vec{x}) = \int \frac{d^3k}{(2\pi)^3}\frac{e^{i\vec{k}\cdot\vec{x}}}{\vec{x}^2 + m^2} Changing to polar coordinates, and writing \vec{k}\cdot\vec{x}=kr \cos\theta, we have: \phi(\vec{x}) =...

Homework Statement A barrel is lowered into a boat using the illustrated apparatus. The barrel can be considered to be a uniform cylinder with M=100kg and r=0.40m. The weight on the other end of the rope has m=30kg. Assume that the barrel does not slip against the wall, that the other 2...

I am currently working on a project and I am stuck on the last question (g). I will provide the questions and my work up until this point. If anyone could help me, it would be greatly appreciated. problems.

http://imgur.com/SnHyP What are the mathematical steps and assumptions to reach the conclusion that length(ab) ≈ dx + ∂u/∂x*dx ? If you consider the the squares of the gradients to be negligible, you still have a square root and multiplication by the constant "2". What other assumptions do...

The S molecule of SO2 forms a double bond with one O and dative covalent bond with another O Meanwhile,XeO4 is a molecule which Xe forms a double bond with each O I have a question here Why doesn't that S forms 2 double bonds with O to extend its octet structure? Similarly,why doesn't that...

Hi folks, I am working through a section on the classical limit of the relativistic doppler shift, but I am stuck on some algebra, I think it should be really basic but I just can't get it to work! My notes go from w = w'(1 - B) to (w' - w)/w = B The context doesn't matter here...

i was reading about derivation of Euler's equations for rotational dynamics (john taylor, classical mechanics, chapter 10) when i got stuck on one of the reasonings essentially it refers to the moment of inertia tensor, since the tensor itself about a point is dependent on the position of the...

While practicing power set problems I came across one that has me stumped. The problem asks: Is the following set is a power set of of a set? {∅, {b, ∅}, {a}, {a, b}, {b}} My answer: This set has 5 elements. Since 5 is not a power of 2, this cannot be the power set of any set. The...

my lonesome have been working on a set of mufflers that don't sound like fecal matter. I am having a difficult time finding just the mufflers (race mufflers). I DO NOT want an entire exhaust system. I do have the capability of fabing up mufflers, I have custom made equal length headers to an x...

Homework Statement A student threw a ball horizontally out a window 8.0m above the ground. It was caught by another student 10.0m away. What was the initial velocity of the ball? ANSWER PROVIDED: 7.16m/s Homework Equations dv=1/2at^2 t=vv/a dh=vht The Attempt at a Solution...

Hello guys i was trying to solve some problem of simple harmonic motion. as it is well explaind in the title I'm not getting the same result as my textbook manual solution. Problem: A block of unknown mass is attached to a spring with a spring constant of 6:50 N/m and undergoes simple...

Hello everyone, I will soon be graduating with a bachelors in physics with a math minor. But lately I've been feeling very apathetic about school, grad school, and even possible work. I just don't want to do anything at all! I don't even know if I like Physics anymore. The idea of going to...

The question is: Henry is bouncing on a trampoline, using the given data below, calculate the height at which Henry will bounce to from his lowest position. Lowest position: -0.50m Henry's Mass: 75kg upward acceleration: 13.3 m/s^2 upward force: 1750N downward force: 750N Net force...

Two packing crates of masses m1 = 10.0 kg and m2 = 4.80 kg are connected by a light string that passes over a frictionless pulley as in the figure. The 4.80-kg crate lies on a smooth incline of angle 41.0°. (a) Find the acceleration of the 4.80-kg crate. QUESTION 1: WHENEVER I'm given...

Pyridine is recovered from coke-oven gases and is used extensively in the chemical industry, in particular, in the synthesis of vitamins and drugs. Pyridine contains carbon, hydrogen, and nitrogen. A 0.546 g sample was burned to produce 1.518 g of carbon dioxide and 0.311 g of water. Determine...

Stuck In "Required" Classes I'm a freshman in college right now. I've tested out of MAT 419, PHYS 460, and CHEM 424. I have to take classes such as ENG 101, PHI 101, and ECN 101. What could I possibly do to start working on the Master's level math, physics, and chemistry courses while I...

When a system is taken from state i to state f along path iaf in the figure, Q = 60 cal and W = 10 cal. Along path ibf, Q = 65 cal. (a) What is W along path ibf? (b) If W = -19 cal for the return path fi, what is Q for this path? (c) If Eint,i = 11 cal, what is Eint,f?(d) If Eint,b = 27 cal...

Very Stuck on Deriving Projectile Motion Formulas Hey, I need some help :( . I've got an exam next Thursday, and I really suck at this stuff right now. So I need to get better! We are studying kinematics (1d and 2d). In this problem I need help with, we are given the attached diagram...

A guy spends 1/6 of his life as a boy, 1/8 as a youth, 1/2 as a man and 15 years as a mature adult. I got about 70 by trial and error but I need to know exactly how to solve it.

Homework Statement The Integral is arctan (4t) dt Homework Equations I know how to do integration by parts, but I guess I have forgotten some of the integration rules. The Attempt at a Solution I set ∫arctan(4t)=u, and dt=dv I know that the derivative of arctan(x) is...

θHomework Statement I'm trying to do an integration by substitution, but I'm completely stuck at the moment ∫(1-sin2θ)cosθ dθ Homework Equations ∫u dv = uv - ∫v du The Attempt at a Solution u = 1 - sin2θ dv = cosθ dθ du = -2sinθcosθ or -sin(2θ) v = sin I found du as...

I need to calculate how much power will be generated by a solar cell at AM1.5. The cell is 1.5x3.5cm^2. I know that it is to do with the area of the cell i just don't understand how to work out the power generated without knowing things like the material. Any help would be appreciated.

Homework Statement A 50 kVA 6360 V/240 V, 50 Hz, transformer is tested on open circuit and short circuit to obtain its efficiency. The results of the tests are as follows: Open Circuit: Primary Voltage 6360 V, Primary current 1.0 A, Input power 2 kW. Short Circuit: Voltage across primary...

When something gets "stuck", what's going on? Hi, So I see things in real life, and wonder what is going on physically. I question things that even seem intuitive. I know most of my questions are stupid, but I don't know much about physics. I just bought "conceptual physics" by hewitt on...

Hi all, I have the following partial derivatives ∂f/∂x = cos(x)sin(x)-xy2 ∂f/∂y = y - yx2 I need to find the original function, f(x,y). I know that df = (∂f/∂x)dx + (∂f/∂y)dy and hence f(x,y) = ∫∂f/∂x dx + g(y) = -1/2(x2y2+cos2(x)) + g(y) Then to find g(y) I took the...

Good Day, I'm stuck on two trigonometry questions. One requires me to prove a trigonometry summation and the other requires me to find the general solution of the given equation. 1. I am required to prove the b/m sin x + sin 2x + sin 3x + ... + sin nx = {sin (n/2)x sin [(n+1)/2]x}/ sin (x/2)...

Homework Statement Figured it would be easier if I showed a picture http://img210.imageshack.us/img210/707/problemcz.jpg Homework Equations Ʃm=0 Ʃfx=0 Ʃfy=0 The Attempt at a Solution Here is my attempted solution, I am missing member BD and not sure which way to solve it, I...

Hi all! I'm stuck with a system of PDE. I'm not sure I want to write it here in full, so l'll write just one of them. I've found a solution to this equation but I'm not sure it's the most general one since when I plug this solution into the other eqs, I get a trivility condition for the...

Stuck on a Torque Problem! Help is appreciated! 1. A mass of 45.5kg is attached to a light string (negligible) that is wrapped around a cylindrical spool of radius 10cm and moment of inertia 4.0kg*m^2. The spool is suspended from the ceiling, and the mass is then released from rest a distance...

Homework Statement Hello friend, i really stuck on how to calculate this thing. I have to find the drag force and lift force acting on fishing lure. By the way, the fishing lure has lip and there an angle on the lip.I am sorry my english is bad but i hope you can understand what i am trying...

Hey guys, I'm hoping someone can help me out, as i have an exam tomorrow and have no began panicing as I've found a question i can't seem to get to the end of... Here is the question itself; A large crucible contains a metal of thermal conductivity, κ = 12.5 Watts. m-1.K-1, electrical...

hi everyone, i am not a math geek and don't know why the hell i chose thermodynamics this semester with this little math knowledge, but can you please help me figure out the basic difference between discrete and continuous probability? in thermodynamics we are sometimes taking the probability...