Homework problem Definition and 419 Threads

  1. T

    Change of internal energy during linear transformation

    A linear transformation is described by: $$p=a-bV$$ From that we can find $a$ and $b$: $$b=\frac{p_{2}-p_{1}}{V_{1}-V_{2}} = \frac{2}{9}\frac{p_{1}}{V_{1}}$$ $$a=p_{1}+bV_{1}=\frac{11}{9}p_{1}$$ I considered an adiabatic process that intersects the linear transformation to find the point up...
  2. A

    Time period of SHM & Energy conservation in pulley-spring-block system

    TL;DR Summary: I was solving this problem given in a book. The answer I got was wrong and seems to violate the conservation of mechanical energy. Yet the forces were balanced. Can someone provide an explanation. So here is the problem: In the above arrangement, I had to find the time period...
  3. J

    Engineering Question on Opamp homework problem: Find Iout between these two Opamps

    Hi, so my objective is to find Io, and I've attached a picture of my work. Here is my question: At the point Vo1, if I use the equation for finding the output voltage for a non-inverting op amp I end up getting this: $$V_{0{1}}=\left( 1+\frac {r_{f}} {r_{1}} \right)V_{s1} = \left( 1+\frac...
  4. C

    The derivative of uv wrt x using st function (homework problem)

    TL;DR Summary: I attempt to find the derivative of uv with respect to x using non standard analysis, hyperreals, and the standard part function st; I take u to be a function of x, and I also take v to be a function of x. Hello everyone! I've been learning about non standard analysis concepts...
  5. lola1227

    Momentum Collision Homework Problem -- help please

    Parallel: M1V1+M2v2=M1V1’+M2V2’ (0.5)(3)+0=(0.5)(cos60)(3)+V2’Cos(x)(0.5) V2’cos(x)= Perpendicular: M1V1+M2v2=M1V1’+M2V2’ 0=(0.5)(0.3)(sin60)+V2’sin(x)(0.5) V2’sin(x)= And the divide 2 by 1 Which is tan(x)=2/1 And then plug then back into solve, but I don’t think we do it like this because...
  6. Robin288

    Electrostatics homework problem help

    Summary:: I been stuck on this problem from past 4 months. I am completely done. I am getting no idea. Even my professor couldn't have helped me. Can anyone please help me? 😔
  7. Jason-Li

    How Do You Simplify Complex Algebraic Fractions?

    So my final equation is: ##\frac {1} {2700} + \frac {1} {3930n^2} + 10^{-5}## I need to boil this down, the learning materials has the following working, but I can't seem to get it $$\frac {1} {2700} + \frac {1} {3930n^2} + 10^{-5}$$ $$\frac {3930n^2+2700+2700*3930n^2*10^{-5}}...
  8. Camden

    Year 10 physics homework problem

    I got this as homework and I am not sure how to attempt it
  9. P

    Are there 2 correct answers to this transformer homework problem?

    Answer B would increase the n1/n2 ratio and increase the deflection. Making it correct. But also, Answer A would increase the current through the primary coil, and hence the power. This would increase the power in the secondary coil hence I2, leading to lower voltage V2. Making it also correct...
  10. jackplaysgames

    Homework Problem Using the Universal Gravitation Equation

    For question A, I know that I am supposed to input the numbers given into the Universal Gravitation Equation, but I do not know how to solve for it beyond that. For question B, I know that the astronauts weight depends on the mass and gravity of the new planet but I do not know how to prove it...
  11. Samama Fahim

    Calculating the Thevenin's Resistance of a Breadboarded Circuit

    How would we calculate the Thevenin's resistance for the above circuit? The right answer for this circuit is 1.5 kOhm. $$R_{567} = R_7 + (R_5 \parallel R_6) = .5 + .67 = 1.2 k\Omega$$ $$R_{34567} = R_3 + (R_4 \parallel R_{567}) = 1 + .75 = 1.75 k\Omega$$ $$R_{TH} = R_1 + (R_2 \parallel...
  12. aligator11

    Engineering Homework problem - Pendulum oscillatory system

    Hi All, Anyone willing to help out in explaining what eigenfreuqncy for this oscilatory system, would be? Also if anybody knows the equation to calulate this stuff please, if you're willing to share I'd be greatful! Thanks, regards.
  13. B

    Electric Force and Field homework problem

    This is my homework. And we don't have online lessons. But my teacher gave this for homework. I couldn't solve this problem. Can you help me?
  14. vinamas

    Earth's magnetic dipole homework problem

    So I'm mainly having trouble with part b as I have successfully completed part a. In part b I get an answer of 6.3 x 10 ^8 Amperes which my homework tool flags as incorrect. I'm clueless as to where to go from there or why my approach is wrong?
  15. F

    Solving a Homework Problem with One Pivot

    Homework Statement https://cdn.discordapp.com/attachments/373928512811302912/528638926148337704/question.PNG part a )50N I cannot answer part b. Homework Equations M=FD The Attempt at a Solution Ok so if both pivots were in contact with the beam I would just equate them with the oppposite...
  16. C

    Finding the energy density outside of an isolated charged sphere

    Homework Statement A charged isolated metal sphere of diameter d has a potential V relative to V = 0 at infinity. Calculate the energy density in the electric field near the surface of the sphere. State your answer in terms of the given variables, using ε0 if necessary.Homework Equations Since...
  17. john-b

    Potential Acceleration of an Atwood Machine

    Homework Statement In the diagram, m1 has a mass of 47 kg and m2 has a mass of 35 kg. The coefficients of friction between m1 and the surface of the inclined plane are µs = 0.42 and µk = 0.19. (a) If the masses are held in place and then released, will they start to move? (b) If the answer...
  18. Tomi Kolawole

    Finding the Magnetic Field of a Point Charge Using Biot-Savart Law

    Homework Statement Homework Equations [/B]The Attempt at a Solution I soled for the integral of the magnetic field but i don't know what bounds to intergrate over and also i what is DS in this case? its a point charge so shouldn't bio savart have q(v*b) instead of i(ds*r)?[/B]
  19. Likith D

    The solution of a problem regarding center of mass

    A rod of mass M (=4m) and length L is placed over a smooth horizontal table. One end of rod is attached with a block of mass m through a light string as shown in the figure. The pulley is friction less and light. the acceleration of com of rod at the given instant is (g = acceleration due to...
  20. A

    How to calculate projectile off cliff when angle is below th

    Homework Statement Cliff is 50 m tall Stone thrown downwards with velocity of 12 m/s and 22 degrees below horizontal What is the time it will take to hit the ground? Homework Equations V=d/t D= Vi t + 1/2at^2The Attempt at a Solution Vx1= cos (22)(12) = +11.12620625 Vy1= sin (22) (12) =...
  21. Irfan Nafi

    Which ball has more energy halfway through the track?

    2 frictionless tracks have equal length bumps with one going up and the other down. Halfway through the track which one has more energy? Assuming that they started at the same height, I thought that they had the same amount of energy, but since Ball B ends up having a greater velocity at the...
  22. C

    Euclidean Methods for BTZ black Hole

    This is an exercise from Hartman's lecture 6th. Using the Euclidean method to calculate the BTZ black hole mass entropy. The BTZ metric is given by $$ ds^2=(r^2-8M)d\tau^2 +\frac{dr^2}{r^2-8M}+r^2d\phi^2$$ and ##\tau \sim \tau+\beta, \beta=\frac{\pi}{\sqrt{2M}}##. Then we calculate the...
  23. H

    How Do You Solve Complex Pendulum Equations in Physics Homework?

    Homework Statement For number 3,4,5 https://s4.postimg.org/qbp3xzq65/IMG_1092.png https://s22.postimg.org/u220j60sx/IMG_1093.pngHomework Equations Centripetal force = m v^2/R T = centripetal force + w Sigma F = m.a The Attempt at a Solution Number 3. Find the v at D point using...
  24. S

    Solving a Homework Problem with Mass, String, and Friction

    Homework Statement There's two blocks of mass m_{A} and m_{B} which are linked by an ideal string. The block of mass A descends at constant speed. There's no friction. If the pulley is ideal, which one of the following is true[/B] Homework Equations Newton laws and trigonometry I...
  25. E

    How Does LIGO Detect Gravitational Waves Using Laser Interferometry?

    Homework Statement In-phase light from a laser with an effective power of 2x105J and a wavelength of 1064nm is sent down perpendicular 4km arms of the LIGO detector. (i) Determine the number of photons traveling in the interferometer arms. (ii) Assuming the detector is sensitive enough to...
  26. T

    Orthogonality of Gravitational Wave Polarizations

    Homework Statement Two plane gravitational waves with TT (transverse-traceless) amplitudes, ##A^{\mu\nu}## and ##B^{\mu\nu}##, are said to have orthogonal polarizations if ##(A^{\mu\nu})^*B_{\mu\nu}=0##, where ##(A^{\mu\nu})^*## is the complex conjugate of ##A^{\mu\nu}##. Show that a 45 degree...
  27. alan

    Isotropic material fitted by Ornstein-Zernike form

    I have known what Ornstein-Zernike equation is. I try to plug in the form as follow to the isotropic materials: Still, I cannot show the pair correlation function as follow. Can anyone know what I have missed?
  28. alan

    Derive approximate expression by regular solution theory

    The question is about to derive an approximate expression by regular solution theory, It is difficult for me to find relevant source on this question. However, the question to me is so vague that I do not know how to answer. What I have tried is to search what the interaction parameter is...
  29. OnlinePhysicsTutor

    Solving Part B of a Homework Problem Involving Principal of Moments

    Homework Statement Please see attached picture Homework Equations principal of moments The Attempt at a Solution part a) is fine. For part b, I would Normally take moments about C. The force acting on BC at B must be the tension in AB. The geometry of the triangle gives and angle of 53.1 to...
  30. Jayalk97

    Engineering Converting to a circuit's Thevenin equivalent?

    Homework Statement Homework Equations Finding the Thevenin equivalent? The Attempt at a Solution I found the thevenin resistance to be 185/47 ohms, which came out to be correct. I've been struggling with this question all day. I ended up attempting to find the norton equivalent and then...
  31. Fetchimus

    Infinite Square Well homework problem

    Homework Statement A particle of mass m, is in an infinite square well of width L, V(x)=0 for 0<x<L, and V(x)=∞, elsewhere. At time t=0,Ψ(x,0) = C[((1+i)/2)*√(2/L)*sin(πx/L) + (1/√L)*sin(2πx/L) in, 0<x<L a) Find C b) Find Ψ(x,t) c) Find <E> as a function of t. d) Find the probability as a...
  32. P

    Solving Part c of Repulsive Force Homework Problem

    Homework Statement (2) Suppose a particle of mass m is subjected to a repulsive force F = +kx. (a) What is the general solution for the motion of the system? (b) If the particle begins with a position x(0) = x0 and with velocity v(0) = v0 at t = 0 what are the values of the constants appearing...
  33. Tspirit

    Wave function homework Problem 2.1 in Griffiths' book

    In the (b),I have some questions: (1) Does it mean ψ can be real or not real? (2) Why do the solutions of linear combination must have the same energy? As I know, these solutions are often different, as long as they are eigenvalues of time-independent Schrodinger equation. (3) In the sentence...
  34. P

    Understanding Far Points and Lens Power in Correcting Myopia

    Homework Statement While carrying contact lenses of D=-2.00 diopters, a nearsighted person takes a vision test and finds that his/her far point is 10.0m a) what is the person's far point without contact lenses? b) what lens power is required to correct the myopia fully? Homework Equations 1/f...
  35. jlmccart03

    Conservation of Energy Homework problem

    Homework Statement A ball of mass m falls from height hi to height hf near the surface of the Earth. When the ball passes hf, it has a speed of vf. Ignore air resistance. Consider the system T which consists of the ball only. Write an expression for each of the following quantities in terms of...
  36. deon0783

    Civil Engineering - Bar Question

    Hey everyone, I'm at my limits here trying to solve a question, I can't seem to figure out how the lecturer gets the solution to the following problem... Can someone please direct me the correct methodology or better yet give me some guidance on what to do? Thank you. The Questions and...
  37. S

    Homework Problem Regarding Linearization

    Homework Statement Hey Guys, I don't really want to have to post this in of all places due to how advanced everyone else is compared to me, but I went to my second physics class and I have a huge problem. My teacher gave me my homework, but I have no idea on Earth how to do it because she...
  38. a255c

    Lagrange optimization: cylinder and plane intersects,

    Homework Statement The cylinder x^2 + y^2 = 1 intersects the plane x + z = 1 in an ellipse. Find the point on the ellipse furthest from the origin. Homework Equations $f(x) = x^2 + y^2 + z^2$ $h(x) = x^2 + y^2 = 1$ $g(x) = x + z = 1$ The Attempt at a Solution $\langle 2x, 2y, 2z \rangle...
  39. normal_force

    KE1 vs KE2, mechanical energy change

    Homework Statement If two objects of unequal mass and unequal Kinetic energy hit each other, they lose some energy to other forms but keep enough to do Work on each other. A good example is a car and wind, a man and ball could also apply, a ball with KE could stop a running man if KE does work...
  40. E

    Solve Homework Problem: Velocity & Force of Rod in Rails

    Homework Statement Two long parallel horizontal rails, a distance d apart and each having a resistance λ per unit length, are joined at one end by a resistance R. A perfectly conducting rod MN of mass m is free to slide along the rails without friction (see the figure). There is a uniform...
  41. T

    How can i solve joint proportion?

    I am currently doing aops introduction to algebra book and I can't figure out how to solve joint proportion or some ppl call it joint variation. I don't which values should i substitute for the formula, z=kxy. I don't which value should i substitute into z to the word problems. I can get through...
  42. gracy

    Equivalent capacitance homework problem

    Homework Statement Find the equivalent capacitance of the combination between A and B in the figure. Homework Equations For Equivalent Capacitance in series ##\frac{1}{C}##=##\frac{1}{C_1}##+##\frac{1}{C_2}##For Equivalent Capacitance in parallel ##C##=##C_1##+##C_2##... The Attempt at a...
  43. jvalencia

    Solving the 2kg Cart Homework Problem

    Homework Statement The figure shows a cord attached to a 2 kg cart that starts from rest and can slide along a frictionless horizontal rail. The right end of the cord is pulled over a frictionless pulley at height h = 2.0 m above the point of attachment of the cord to the mass, so the cart...
  44. ProjectTruth

    How Much Does Each Golf Ball Cost in This Algebra Problem?

    << Mentor Note -- Thread moved from the technical math forums, so no HH Template is shown >> Hey guys, could use some insight here... So this is a basic story problem: "I paid $22.30 for 6 new golf balls and 10 used balls. If each new ball costs $.65 more than a used ball,how much did I pay...
  45. A

    Investigate one factor that affects the angle of refraction

    Statement: I need a suitable method and factor to investigate ONE factor that affects the angle of refraction. It has to be related to the context of everyday life and glasses, i.e. how glasses are used to focus light and the light focused is that of a refracted ray. Therefore factors such as...
  46. L

    Solving Homework Problem #16ii: Log([x+y]/sqrt5)

    Homework Statement I am having problem with number 16ii) Homework Equations log([x+y]/sqrt5) The Attempt at a Solution Sorry still not used to latex So I tried this if x/y + y/x =3 then( (x^2 + y^2)/xy = 3xy x^2 + y^2 = 3xy (x-y)^2 = xy (x-y) = sqrt(xy) (x-y)(x+y) = sqrt(xy)(x+y) (x+y)...
  47. M

    Water Pressure Homework Problem

    Homework Statement A person swim to certain depth in the ocean where the density of sea water is 1025 kg/m3. he does not have sophisticated equipment but he used an empty tube, the tube is L = 45.4 cm long and shaped like a cylinder. He wets the sides and then puts some sand in and shakes it...
  48. RaulTheUCSCSlug

    Solving index of refraction for Total Internal Reflection

    Homework Statement Homework Equations Snell's Law n1sin(theta_1)=n2sin(theta_2) Total Internal Refraction: sin(theta_c)=(n_2/n_1) lambda_n=lambda_n The Attempt at a Solution So I drew the triangle and this is what I got, and well here is just a picture so far of what I have. [/B] I've...
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