Stuck Definition and 836 Threads

Hi there, I'm helping tutor a friend in astrophysics and I've come across a question I can't answer - which is annoying and embarassing to say the least :) The question reads: (a) Calculate the kinetic energy and pressure involved when the Earth gets hit by a stony meteoroid (ρ = 3400...

The problem: (See attachment) I rationalize the numerator and then simplify to get: lim (3(1+sqrtx) - 2(1+cubert(x)))/(1-x) x->1 However, I do not know what to do after this point. If someone could please help me out, that would be great! Thank you! P.S: Look carefully at the...

I could do with some help here about a problem I had at work today. I have a process that dumps 8 parts in a bin every cycle. Each part is numbered, 1 to 8. (It is a big bin and it will contain an equal quantity of each number). I need to measure one part of each number, so I need to grab a...

Homework Statement Solve 5x^2 - 16tx + 3t^2 for x without using quadratic formula. I am interested in understanding the technique - I have the answers already: t/5, 3t Homework Equations I have solved the subsequent question which is: tx^2 + (tT - 1)x - T = 0, which seems easier because...

Hi all sorry the title couldn't be more descriptive. I'm having a bit of a brain block with this equation (it's the very end of a problem). N(\frac{5}{6})^{N-1} > \frac{27}{5} My line of thought was to get the first N in terms of the power N-1.. How do I find N?

Stuck please help -- 117.72=100sin2x + 28cosx Im trying to find an angle and I am stuck 117.72=100sin2x + 28cosx What do i do now?

Hello everybody, I am doing ICS Btec Mech Eng course at the moment and I've stuck in a question about frictions. So I have to explain journal friction, bearing pressure, sliding friction and rolling friction in relation to friction. I've found following: Sliding friction appears...

Here's the problem I was given: Find the area of the surface generated by revolving the curve $$x=\frac{e^y + e^{-y} }{2}$$ from 0 $$\leq$$ y $$\leq$$ ln(2) about the y-axis. I tried the normal route first... g(y) = x = $$\frac{1}{2} (e^y + e^{-y})$$ g'(y) = dx/dy = $$\frac{1}{2} (e^y -...

Hey guys! Having issues with a code I'm writing. It doesn't fit the typical format and I may have already accidentally posted it in the wrong forum, so here's a copy of what was there with the newest version of the code. It'll (eventually) be a four-parameter least squares minimisation, but for...

Hey guys! Having issues with a code I'm writing. It'll (eventually) be a four-parameter least squares minimisation, but for the moment I'm just trying to get the single parameter version to work. I've got the first module done but, when I run it it gets caught up in a loop and doesn't actually...

Homework Statement For the circuit in question1above: R=(3.74x10^2) (Ω), C=(3.8700x10^-7) (F), f=(4.610x10^3) (Hz) and the peak amplitude of the voltage of the source (ES)=(6.185x10^1) (V). Calculate the instantaneous value of the voltage across the capacitor at t=(4.110x10^-5) (s) after the...

So as I have been completing my physics homework, there is one question I can not get passed. However I feel as if I already have the answer. The question is: What is the speed of the car 10.0 s after it begins its motion if it continues to move with the same acceleration? The original...

Hi all - I was having a debate with some students in my flipped class today and I can't wrap my head around Bernoulli's Principle as it relates to the sea. Can anyone explain how Bernoulli's principle works with a sail boat? I don't know how the force vectors resolve to push a sail boat...

Here is my task and attempt for solution: As you can see, I tried with substitutions but I have no idea what to do next. Any suggestion?

:mad: I really hate these problems. (2+√7)/(3-√-11). What the heck? I start out by multiplying both sides with the conjugate again. This is where I am stuck lol. Can someone tell me what I am doing wrong while multiplying the conjugate? (3 - √-11) is the same as 3 - √11i correct? So I...

I can't believe I've been stuck on this the whole day... I'd appreciate any help. Suppose G is a free abelian group, and even feel free to assume it's finitely generated. H is a subgroup. I'm trying to prove that Rank(G/H) = Rank(G) - Rank(H). Also, I'm looking for the most basic proof. (I...

Simple C programming problem, variable "stuck" at initialised value Hello! This is most likely an error in my code but I just can't see what it is! I am new to C programming and maybe I have just been staring at it for so long that I can't see the obvious error. I was playing around with a...

Question; A rocket launched at 70 degrees to the horizontal has constant net acceleration of 8m/s^2 along its path for 6.5 seconds and then is in free fall! What is the rockets maximum height? Ps answer is 281m I couldn't help but look lol Solution attempt: From the net acceleration I got...

Homework Statement find the series solution to y''+x^2*y'+y=0 Homework Equations y=summation from n=0 to infinity Cn*x^n The Attempt at a Solution y=sum from 0 to inf Cnxn x^2*y'=sum from 1 to inf nC n xn+1 = sum from 2 to inf (n-1) C n-1 xn = sum from 1 to inf (n-1) C n-1 xn...

Homework Statement The total power radiated by an oscillating electric dipole is a function of the oscillation frequency ω, the dipole moment p(=Qd, where ±Q is the charge at each end of the dipole and d is the distance between charges), the speed of light c and the permittivity of free space...

Hi guys! I have never used statistics in my life, so now I'm completely lost. I have only 3 variables - the year of the company founding (up to 1993, 1994-2004, 2005-now), the technological intensity of their products (that's either a, b, c or d) and the number of foreign markets (that's...

Hello, So here we are, back to the same old problem that we had back in 2012. I am finding myself not enjoying chemical engineering or really any of my technical classes. The honest truth is that they are just straight up boring, and not to mention that I have to inch and claw my way through...

I'm trying to figure out the convection coefficent between aluminum 4032 and steel in w/m^2*k 400w-500w? No Reason being I'm running a simulation of a thermal loaded aluminium detail, that is in contact with a steel plae. The upper part is heated by an external source. I need the...

Stuck in this question -- 2 spinning disks brought together... Two disks are spinning freely about axes that run through their respective centres. The larger disk (R1 = 1.42 m) has a moment of inertia of 1180 kg · m2 and an angular speed of 4.0 rad/s. The smaller disk (R2 = 0.60 m) has a...

So, I have this DE which is 2nd order, w/ variable coefficients, it goes; xy''+(x-5)y'+(x^2-4)y=0 revolving around x_0=4. I know there's a singular point at 0 and I assume to use a summation y(x)=[∞,Ʃ,n=0] a_n(x-x_0)^n pardon me I don't know how to type the summation symbol, but that's...

Homework Statement The question is from Sakurai 2nd edition, problem 3.21. (See attachments) ******* EDIT: Oops! Forgot to attach file! It should be there now.. *******The Attempt at a Solution Part a, I feel like I can do without too much of a problem, just re-write L as L=xp and then...

Homework Statement 2) In the variant of Atwood’s machine shown below, a mass slides on an inclined surface 40θ above the horizontal with a coefficient of kinetic friction μk = 0.15. The masses M1 and M2 are 1 kg and 2 kg, respectively. Which way does the pulley rotate? If the lowest point of...

I was practicing this question which is \int \frac{cos(5x)}{e^{sin(5x)}} dx let u=sin(5x) then \frac{du}{dx}=5cos(5x) which can be rewritten as \frac{1}{5}du = cos(5x) dx Substituting u in gives \frac{1}{5} \int \frac{1}{e^u} du This is where I get messed up. Can't you rewrite \frac{1}{e^u} as...

Homework Statement Find the equivalent resistance of: https://www.circuitlab.com/circuit/5s3ebn/screenshot/1024x768/ Homework Equations The Attempt at a Solution I've simplified it a bit already... Just very confused in regards to which resistances are in parallel since they...

Hi there! I am stuck on how to work out the integral of 1/(2^x) and was hoping someone could guide me step by step to the answer? so confused and would really appreciate the help thanks!

Trying to make a calculation and I ran into the following diff equation: r''=a+b/r^2 And I can't seem to remember how one would go about solving it. b = 1355041.84 r(0) = 1400 r(t) = 239.6 r'(o) = 0 r'(t) = 75.2 a = ? I'm specifically looking to find the value of the constant a...

Homework Statement a cannon is fired out of a cannon at a velocity of 28m/s and at an angle of 90°. Straight up. Assume it starts at a height of 0, figure out the max height it will reach. Air resistance is ignored. Homework Equations The Attempt at a Solution I'm not 100% on this but...

S=8x2ln(1/2x) Find the value of x that gives a maximum. So far I have got, by differentiating: x2+ln(1/2x). [could be wrong] Btw the way in the question x is a ratio and so cannot equal zero. Please help and explain how to do it thanks :)

Hey everybody I'm developing a computer program that can take a series of data-points and estimate the next local maximum(top) of a sine-curve. My approach to this is to take the formula for a sine-function(f(x)=Asin(\omega x - \phi) + B), and isolate all the variables, and that way I'll...

2) I am unsure why the answer is A.. I thought the answer would be C ( by using flemings left hand rule) 5) If we resolve forces, we get R - mg = mv^2/r , so R = mg + mv^2/r but this isn't the correct answer.. (the correct answer is D) 6) I know when lines of flux are cut, an EMF and therefore...

Hi, here is a very simple solution mixing problem that I can't solve which I am really ashamed of. Problem. A vessel whose capacity is 5 liters contains 2 liters of 15% salt solution. How many liters of 20% salt solution have to be mixed to the 15% solution to produce a solution with as high...

I am trying to solve this ODE and am stuck on this step! It is a mass balance of a tank where the volume and concentration are changing by time Fin*Co - Fout*C1 = d(C1*V)/dt Fin*Co - Fout*C1 = d(C1)/dt * V + d(V)/dt * C1 where V = A*h (area and height, where area is constant and height...

I know this is quite simple question. An object has an into all velocity of 50m/s it's traveling straight up. Assume g=-10m/s^2 how long does it take to go up and down? I put these numbers into x=1/2at^2+vi*t but I still have 2 variables. X and T. Idk what to do.

Homework Statement Two blocks m1 and m2 are at rest, each on a frictionless plane and are connected by a massless rope passing over a frictionless pulley. The pully is at the top of where the two planes connect to make an angle of 90 degrees. the plane with m1 is to the left and makes an...

Homework Statement I'm stuck on a relatively simple exercise which can be found in Callen's book: Show that if ##\alpha = \frac{1}{T}## then ##c_P## is pressure independent.Homework Equations What they ask me to show is: If ##\frac{1}{v} \left ( \frac{\partial v }{\partial T} \right )...

Hi, I hope there is no issue with me posting this here but I'm stuck trying to get my head around DrChinese's page on Bell's Theorem. "ASSUME that a photon has 3 simultaneously real Hidden Variables A, B and C at the angles 0 degrees, 120 degrees and 240 degrees per the diagram above. These 3...

My first post let's see if i did this typing right, if not please forgive me... Homework Statement \int \frac{(1+ln x)^2}{x}\,dx Homework Equations Trying to attack it by using substitution.. The Attempt at a Solution Using... u = 1 + ln(x) , du = 1/x \begin{align} \int \frac{(1+ln...

Homework Statement A particle of mass m is inside a 1 dimensional "box" of length L such that it's restricted to move between ##x=-L/2## and ##x=L/2## where the potential vanishes. 1)Determine the eigenvalues ##E_n## and the eigenfunctions ##\psi _n## of the Hamiltonian imposing that the...

The question goes like this: Suppose a phone number is 123-4567, and that the first three numbers and last 4 numbers are scrambled. First parts I figured out: Probability of choosing every number correctly: 1/3!4! probability of choosing of choosing the first 3 correctly:1/3! Where I got stuck...

Homework Statement Use implicit differentiation to find y' given y/(x-y) = x^2+1.Homework Equations The Attempt at a Solution Hi, I'm doing an online course for Calculus 12, and I have been struggling with Implicit Differentiation. I am hoping someone could maybe help me. Thanks. I'm not...

Hi, I'm doing an online course for Calculus 12 and I have been struggling with Implicit Differentiation, hoping someone could maybe help me. Thanks. I'm not positive I'm doing this right but maybe someone can point me in the right direction, this is what I have so far y/(x-y) = x^2+1...

I have a MSc in astrophysics and I'm a last year PhD student. My project is not going anywhere, I haven't published any paper and I'm far from finishing. My advisor is very picky and won't let me publish anything and I'm terrified the last years have been a huge waste of time. What do you think...

Can someone please break down how to do this one? I'm absolutely stumped on this one. Thank you very much. :)Use the following sets to complete the operations. Universal set = {lower case English letters; a,b,c,d…x,y,z} V = {a,e,i,o,u} S = {letters in the word “spring”} G = {letters in the word...

Hello, I am thinking of going to college this year and I have 3-4 options(Physics with Computer Science, Engineering Physics, Electrical Engineering, Mechatronics)... First of all I like to have a lot different experiences, with different things, I do not want to pe specialized but more of a...

The two cars have identical horns, each emitting a frequency of fs = 410 Hz. One of the cars is moving with a speed of 8.0 m/s toward a bystander waiting at a corner and the other car is parked. The speed of sound is 343 m/s. What is the beat frequency heard by the bystander? my attempt at the...