1. T

    Origin of Gibb's free energy

    Gibb's free energy gives the energy which is easily available in the system, it can be used to do work. But I wonder what is the origin of the Gibb's free energy? Can anyone explain at the molecular point of view? As in, say the electrons are in a random state of motion, so the collective energy...
  2. R

    Free Body Diagram

    Please , could any body help me to draw the free body diagram for the below problem ? assume that the static friction coefficient between the sloping beam and the ground is us . Thanks in Advance
  3. M

    Free surface flow

    ''' The surface can move with the fluid and so must be found as part of the solution '''; How can consider the surface as part of solution?! this topic is depends on flowing of fluid with free surface perturbed by an obstacle.
  4. G

    Free body diagram

    Greetings! I could need some help on the following problem. 1. Explain force and momentum equilibrium for a free body and the division of forces in composants. Show how these are used to determine the forces on the two rods in the figure. 2. Explain what tension there are in the rods...
  5. T

    Mechanics II: Hamiltonian and Lagrangian of a relativistic free particle

    The Problem: I am given the Hamiltonian of the relativistic free particle. H(q,p)=sqrt(p^2c^2+m^2c^4) Assume c=1 1: Find Ham-1 and Ham-2 for m=0 2: Show L(q,q(dot))=-m*sqrt(1-(q(dot))^2/c^2) 3: Consider m=0, what does it mean? Equations Used: Ham-1: q(dot)=dH/dp Ham-2: p(dot)=-dH/dq...
  6. K

    Free Fall Problems (Urgent)

    I'm working on a homework and I've found there's a problem I can't find a solution to: A boy throws rocks up to a height we will name "H". How far must he throw the rocks for them to be twice the time in the air. -At first, the problem seems easy, as it is obvious that if it takes a...
  7. pittsburghjoe

    Unobserved, Free particles in the state of superposition is proof of a 4th dimension

    String Theory needs 10 dimensions to function, but most people have a problem with it because we don't have proof of extra dimensions ..well here ya go. A free/single particle is physically created (with mass in the three dimensions we are familiar with) when a conscience being acknowledges...
  8. O

    Electricity free Air cooling ???

    There are a few videos on Youtube of people installing what they believe to be AC units ... It consists of a bank of cut off water bottles large diameter outside , a breeze enters the the bottle , exits through the narrow top inside the house at higher speed , they claim this reduces the...
  9. B

    Subregular gibbs free energy

    Hello fellows, I have an question about subregular binary solutions. I am wondering whether there are equations for gibbs excess free energy for subregular solutions or not? I have a homework, I am a bit confused how to do it? Thanks in advance!
  10. L

    Free particle hits potential step. Wavelength of particle and amplitude of wave?

    A free particle with energy E hits a potential step with $U_0 > 0$ at $x \geq 0$. Assume that $E > U_0$. (1) Determine the wavelengths associated with the particle in the area $x > 0$ and in the area $x < 0$. (2) What is the relationship between the amplitude of the transmitted wave in the...
  11. L

    free fall fluid of body

    why when the fluid container is accelearting upward , the pressure gradient in z direction is -2 ρ g ?
  12. kelsiu

    Reflected wave from free end

    A wave pulse on a string moving from left to right towards a free end will reflect and propagates from right to left with the same speed and amplitude as the incident wave, and with the same polarity. My question is, why the slope and the vertical force must be zero at the free end? If the...
  13. kelsiu

    Why dU may not equals dW in free expansion?

    From a video lecture, it is mentioned that "dU≠dW in Joule's free expansion if the process is irreversible and adiabatic" Mentioned in around 36:00-38:00 in the video: What I would like to ask is why in this irreversible adiabatic process, dU≠dW? Is...
  14. T

    Help with free body diagram for a pendulum

    I wrote the summation of forces perpendicular to the inverted pendulum and the summation of the moments about the centroid of the pendulum. I am not sure if they are right (especially the signs) and was wondering if someone could check
  15. T

    Free fall that landed on a head!

    Hi, I am not a physicist, just a civilian here! My well-driller husband had a piece of steel land on his head. It fell 45 feet, minus his height of 6 feet so 39 feet, and weighed 7 pounds. He lived. He has a concussion but not a bad one. We were wondering if someone could help us understand the...
  16. S

    Free Body Diagram help?

    What am I doing wrong for this free body diagram? Says it is wrong It is car accelerating to the right. I need normal force, weigh, drag force, and friction vectors.
  17. Y

    College physics- Free fall problem .

    An airplane is flying with a velocity of 85.0m/s at an angle of 20.0∘ above the horizontal. When the plane is a distance 111m directly above a dog that is standing on level ground, a suitcase drops out of the luggage compartment. How far from the dog will the suitcase land? You can ignore air...
  18. P

    Energy in a free vortex of water

    Hey guys, I'm actually working on a project of gravitational vortex turbine at an undergrad level. I need to know the energy or the energy required to make a stable free vortex in a cylinder. The cylinder is of 1 m height and 1.5 m diameter. A channel of 0.5 m width is connected to the...
  19. F

    bicycle free body diagrams/analysis

    Hi all, I really struggle when it comes to things like this! I've designed an electric bike frame, and I want to roughly calculate the distribution of the loading just to have something to back-up my Solidworks model. I found this:
  20. M

    Fun with kinematics and dynamics - free pdf book

    The new edition of the free physics text in pdf format is now online at The new 26th edition includes many new topics, pictures, puzzles and tables; it keeps the promise to be fascinating and challenging on every page. The new edition adds various...