Homework Help
For assistance with (but not answers to) homework problems.
A simple reminder to all: this is the "Homework Help" forum, not the "Homework Answers" forum. We will not do your work for you, only point you in the right direction. Posts that do give the answers may be removed.
5178 topics in this forum
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how do you calculate specific heat capacity? if you can work an example that would be great!
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I have started this thread to help cloudzell91 with an idea for a thesis project. He needs more than one to present to his adviser. The original idea came from one of the Knuth "Fundamental Algorithms" volumes, as I recall. I do not have a copy to verify my memory and extract a quote. However, the quote said something to the effect that programming languages cannot modify their own syntax, as spoken languages can. That peaked my curiosity and started me on a lifelong quest to satisfy my curiosity about how it may be done. Several years later, I worked for Datapoint, a minicomputer manufacturer, who had developed a scripting language called CHAINPLUS, which had fun…
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Hello, my teacher gave me this question and seems like none of my classmates know the answer. I understand that first I have to find a compund that reacts with HCL to find the first letter "A" but how do I do that? Thank you in advance for the ones willing to help me Compound X was treated with Hydrochloric acid to give compound A, a primary substituted compound. Compound A was then treated with aqueous sodium hydroxide to give compound B and sodium chloride as products. Compound B was oxidized to compound C which was further oxidized to compound D. Compound D was found to have a formula of C3H6O2 and had a pH <7. Compounds B & D reacted with one another in the…
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Hello. I have got homework for tomorrow and I have some difficulties doing it, can you please help me doing it? Thanks BTW, its not necessery to do the essay so I will do it on my own.
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Lions and tigers are two closely related species which evolved from a common ancestor. Explain how moving to different habitats has resulted in the formation of these two different species.
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in case of turbine it is said the work is done by the system and for compressor it is said that the work is done on the system.in case of turbine steam moves the blades and in case of compressor air moves the piston.then where is the difference in regard to work done or work by???
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Hi!!! Which is the parametrization of z= y^2-x^2 , and f(x,y)=(-x,-y,z) ???
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a math problem goes like this a gas initially at p1=512 kpa and v1=142 litre undergoes a process to p2=172 kpa and v2=274 litre durig which enthalpy decreases 65.4 kj.specific heats are constant,Cv=3.175 kj/kg-k.determine dU,Cp and R. here my question is 1) I cant understand which thermodynamic process is this,isothermal,polytropic or adiabetic.and why??
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Hii!!! I hope someone can help me with the following exercise...!!! Let G=(V,E) be a directed graph with weight w: E->R, n=|V|. Let m( c )=1/k*sum(w(e_{i}), i=1,k) be the mean weight of a circle. Let m*=min(m( c )), the minimum of the mean weights of the circles of G. Is it correct to say that, since the minimum of the mean weight is 0 and not negative, there are no circles with negative weight? Or is there an other explanation that if m*=0 there are no circles with negative weight..??? And also, how could I explain that δ(s,v)=min(δ_{k}(s,v), o<=k<=n-1), where δ(s,v) is the weight of the lightest path from s to v, and δ_{k}(s,v) is the weight of the light…
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octane is burnt with 80% air if it is theoritical air ,the equation wiill be C8H18+a(O2+3.76N2)------>xCO2+yH2O+a*(3.76N2) and form that equation we can find the coefficient a,x,y. for x=8; 2y=18, so y=9; 2a=2x+y, so 2a=2*8+9, a=12.5 but when it comes to less than theoritical air there should be co present ,shouldn't it? then what will be the equation c8h8+a(o2+3.76n2)----->xco2+yh2o+a*(3.76n2)+co if i give some coefficient to co my question is how i can find the value coefficient of co here ?
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Hi!!! I need some help at the following exercise... Let G=(V,E) be a directed graph, where V={a,b,c,d,e}, E={(a,b),(a,e),(b,c),(c,d),(d,e),(e,c)} and their weights 1,2,2,-1,-1,3 respectively. Show where the Dijkstra's algorithm fails. What I've done so far is: At the beginning the distances are d[a]=0, d=d[c]=d[d]=d[e]=infinity a gets extracted first, after the edges (a,b) and (a,e) are relaxed, and the distances are d=1, d[e]=2. b is extracted next, after the edge (b,c) is relaxed, and d[c]=3 then c is extracted,after the edge (c,d) is relaxed and d[d]=2 At this step I have difficulties... Now d[d]=d[e]... How do I continue??
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1, Prove the following: (i) [latex]if, ax = a[/latex] for some number [latex]a \neq 0, then, x = 1.[/latex] (ii) [latex]x^2 - y^2 = (x-y)(x+y)[/latex] My Answer: (i) if [latex]ax = a, a \neq 0[/latex] [latex]ax * a^{-1} = a * a^{-1}[/latex] [latex]x * a * a^{-1} = a * a^{-1} = 1[/latex] [latex]x * 1 = x = 1[/latex] (ii) let [latex]y = x +k[/latex] then [latex]x^2 - y^2 = x^2 - (x+k)^2[/latex] [latex]= x^2 - (x^2 + 2xk + k^2)[/latex] [latex]= x^2 - x^2 -2xk - k^2[/latex] [latex]= -2xk -k^ = -k(2x+k)[/latex] then [latex](x-y)(x+y) = (x - (x+k))(x + x +k)[/latex] [latex]= (x-x-k) (2x +k)[/latex] [latex]= (0-k)(2x+k) = -k(2x +k)[/latex] Thus, [late…
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1. The problem statement, all variables and given/known data find dy/dx for the function xy^2+xlnx=4y for x>o 2. Relevant equations xy^2+xlnx=4y 3. The attempt at a solution I found the dy/dx to be "(y^2+lnx+1)/(4-x)=dx/dy" What is it asking me to do with the x>0? Do they want me to plug in a value greater than 0 for x and solve for y? or what?
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I'm taking an online course so there is no teacher to check my work. Thanks in advance! ps. don't worry about #4.
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which of the following mostly accurately describes why a plastic, air-filled ball expands in the sun? a) when they heat up the air molecules expand b) when they heat up molecules making up air expand c) when they heat up, the distance between the air molecules expands. d) when they heat up the distance between the molecules making up the air expands.
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what is "equivalent molecular mass " means and how to determine it from mole fraction ????
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Please forgive me for my ignorance but my studies with regards to NMR was lifetimes ago! I work with Polyurethane systems and my question with regards to these is the following: If the polyurethane material is cured out (like a hard plastic like PE or ABS rigid) would there be any detectable signal in a NMR test and/or in a MRI instrument? My thought is that as long as the polyurethane is 100% reactive it is solid and kind of in a pseudo frozen state, a state in which the electrons are not readily manipulated by the magnetic field for alignment as well as less susceptible for RF deflection. I could imagine that if a unreactive material is used like a plasticizer it wil…
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Are my calculations to graph this function [f(x)=(-5x^2+3x)/(2x^2-5)]correct? Can you please check them over and see if I have done this wrong?
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The problem statement, all variables and given/known data Find the critical point of f(x)=(-5x^2+3x)/(2x^2-5), and show whether this point is a max/min. Relevant equations f(x)=(-5x^2+3x)/(2x^2-5) The attempt at a solution When I tried solving for the derivative of; f(x)=(-5x^2+3x)/(2x^2-5), I got (-6x^2+50x-15)/2x^2-5)^2. then I set it equal to 0 and I got 0=-6x^2+50x-15 Now from here do I use the quadratic formula to solve for x? I tried that and I am getting x=(25+sqrt535)/6 and x=(25-sqrt535)/6. Have I done it right so far? When I try to plug in the x-values into the original eq to get y my calc says error... What do I do now?
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Hi!! I want to use the fixed point iteration for the Backward Euler Method for 2x2 systems(in Matlab), I wrote the following that appreciates it: function [Y1,Y2]=stage(y1n,y2n,h,tn) M=5; TOL=1e-5; x1(1)=y1n; x2(1)=y2n; for m=1:M x1(m+1)=y1n+h*S(tn+h,x1(m),x2(m)); x2(m+1)=y2n+h*G(tn+h,x1(m),x2(m)); if (abs(x1(m+1)-x1(m))<TOL || abs(x2(m+1)-x2(m))<TOL) Y1=x1(m+1); Y2=x2(m+1); return end x1_m=x1(m+1); x2_m=x2(m+1); end Y1=x1(M); Y2=x2(M); Could you tell me if the "if" loop has to stop either if |(x1(m+1)-x1(m)|<TOL or |x2(m+1)-x2(m)|<TOL , or…
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I'm taking an online course so I have no one to give me feedback before I submit my assignments. Can you please tell me what I got wrong and what's wrong about it?
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Question: Two small spheres, each having a mass of 20 g, are suspended from a common point by two insulating strings of length 40 cm each. The spheres are identically charged and the separation between the balls at equilibrium is found to be 4 cm. find the charge on each spheres. What I have done: Given, m = 20 g distance between the balls = 0.04 m length of strings = 0.4 m After making a free body diagram, I got two equations. Tcosθ = F (electrostatic force) Tsinθ = mg Dividing the two, tanθ = mg/F - (i) Now, looking at the triangle made in the figure, I dropped a perpendicular from the vertex from where the two strings are joined. Looking at the…
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Hi Can please give me the idea for solving this quetion A Carnot engine operates between reservoirs at 20 and 200°C. If 10 kW of power is produced, the rejected heat rate is nearest
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I need to simplify cos⁻¹[(2x - 3√(1 - x²))/(√13)] Any ideas to how to do so?
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Hi Can please give me the idea for solving these two questions
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