Dynamics Definition and 1000 Threads

  1. Kushwoho44

    Fluid Dynamics: Static Thrust on a Conv-Div Nozzle

    Homework Statement The attempt at a solution Hi all, I am tasked with finding the static thrust generated by this convergent-divergent nozzle. The stagnation pressure is known the inlet. Now, personally, I would've thought drawn a control volume around the entire nozzle. And then said...
  2. Buzz Bloom

    Orbit Dynamics in an Expanding Universe

    After learning a bit from the thread "The Dark Sky Ahead", I have tried to think through the dynamics of gravitational interactions in a simplified scenario. Unfortunately the GR math of the problem is over my head. My attempt below, using a simpler approach, leaves me quite confused. If my...
  3. F

    Fluid Dynamics: Static pressure in compressible Liquids

    Homework Statement [/B] "Derive a relation between the static pressure P at a point and its depth y from the free surface of the liquid. Given the surface density of liquid is ρο, and compressibility of the liquid is k." Homework Equations ##ρ(P) = ρ_οe^{kP}## ##dP = ρg dy## The Attempt at a...
  4. P

    What is the new Hamiltonian constraint operator for loop quantum gravity?

    A critique of LQG here: "The next step in the construction of LQG is to decide what the dynamics are. Technically, this is done either (A) by choosing a "Hamiltonian constraint" in parallel with the Hamiltonian formulation of GR, or (B) in the spin-foam formalism, by postulating some sort of...
  5. J

    Struggling to Understand Pulley System Dynamics

    Homework Statement it is Problem 3.30. Homework Equations I am not sure how to sum the forces about each consecutive pulley I have been at this for 4 hours now. It is sad I can solve the DE questions and not this. The Attempt at a Solution I had the first pulley at the top as (where y is...
  6. S

    Modified Newtonian Dynamics vs. Quantum Gravity

    OK. I'm sure this is probably been considered before but it is my musings coming off a recent attempt to photograph the Andromeda Galaxy. I did a few two minutes or so shots of Andromeda and stacked them for a total of about 14 minutes. Fairly nice. There is some structure to be seen but...
  7. upender singh

    What Is the Stiffness Constant k of the Spring?

    1:question A weight W is suspended from a rigid support by a hard spring with stiffness constant k . The spring is enclosed in a hard plastic sleeve, which prevents horizontal motion, but allows vertical oscillations. A simple pendulum of length l with a bob of mass m (mg<<W) is suspended from...
  8. Feodalherren

    How Do You Continue the Proof for the Dyadic Product in Fluid Dynamics?

    Homework Statement Hi, I wasn't sure whether to post this here or in the engineering forums. Since it's mainly math/theory I figured here would be more appropriate. Feel free to move it if it doesn't belong here. All relevant info etc. is in the picture, thanks. Homework Equations The...
  9. M

    Can Quarks Move Between Nucleons or Change Arrangement Within One Nucleon?

    The strong interaction keeps the quarks in very stable triplets or due to internal dynamics the quarks are re-arranged in nucleons from time to time?
  10. A

    Doubt with Greenwood's dynamics book

    Hi, in order to upgrade my knowledge in dynamics, I am starting a more advanced course by myself, and the two recommended books were Principles of Dynamics and Advanced Dynamics, both by Greenwood. I would like to know what is the difference of this two books, which one is harder? Thanks anyway.
  11. J

    Engineering Dynamics: Solving Train Decel on Slope

    Homework Statement The 160-Mg train travels with a speed of 80 kmlh when it starts to climb the slope. If the engine exerts a traction force F of 1120 of the weight of the train and the rolling resistance F D is equal to 1/500 of the weight of the train, determine the deceleration of the train...
  12. R

    What causes the liquid to rise in this picture?

    This is a diagram of a pitot-static tube. My question is however not related to its applications but rather, what causes the liquid to rise up the static tube? The static tube is at right angles to the fluid flow. I understand that this is a very basic question but I can't seem to get my head...
  13. A

    Inverted pendulum balance dynamics equations

    Homework Statement Hi guys! I am reading a paper on inverted pendulum. However, I can't understand the dynamics equations of this inverted pendulum. You may look at the images below. Basically the thruster is placed at top plate, while the middle plate is a base plate where pivot is placed. And...
  14. A

    Hypodermic Needle Fluid Dynamics

    A hypodermic syringe contains a medicine with the density of water (figure below). The barrel of the syringe has a cross-sectional area of 2.18 10-5 m2. In the absence of a force on the plunger, the pressure everywhere is 1.00 atm. A force of magnitude 1.78 N is exerted on the plunger, making...
  15. M

    How long will it take for a gas tank to empty?

    Hello all, I have an oxygen tank that is 10 L in volume, pressurized at 500 barr (pressure can be adjusted down to 1 barr out of the tube), and I want to 'bubble' the oxygen into a beaker of water. I will simply use a tube (diameter is around 0.5 cm) connected from the tank and with the other...
  16. P

    What direction would you take answering this question?

    Homework Statement Planning a new stunt where he will be shout out of a cannon into the back of a speeding utility vehicle the sit slopes downhill at 10 degrees and the cannon will launch him at 35Km/Hr at and angle of 30 degrees as shown in the attached picture Homework Equations I cannot...
  17. ltkach2015

    Dynamics Problem: Not Understanding the Acceleration Term

    Homework Statement [/B] If particles at B and C of equal mass m are connected by strings to each and to points A and D as shown, all points remaining in the same horizontal plane. If points A and D move with the same acceleration a along parallel paths, solve for the tensile force in each of...
  18. duran9987

    Motion On An Off Center Circle In Polar Coordinates

    Homework Statement A particle moves with constant speed ν around a circle of radius b, with the circle offset from the origin of coordinates by a distance b so that it is tangential to the y axis. Find the particle's velocity vector in polar coordinates. Homework Equations (dots for time...
  19. L

    Find the angular acceleration of the rod

    Homework Statement Given: ##\mu_B=0.52## ##\theta=30^{\circ}## Weight- ##25## lb ##\omega=0## ## l=6## ft ##r_c=3\sqrt 2## radius of curvature. Homework Equations My Equations of motion are the following: ##\xleftarrow{+}\sum F_x=N_A\sin 60 - F_B=0## ##\downarrow{+} \sum F_y= N_A \cos...
  20. manongistong

    Solve Trigonometric Problem for Dynamics: 4th Hint Equation

    This problem is same as the problem on this link https://www.physicsforums.com/threads/trigonometric-problem.76696/ . I would like to ask the number 4 hint which is "4) We therefore have, for example the equality: " the equations can't be seen on my pc as it will only outputs this...
  21. A

    Is the answer key wrong? Physics 12U Dynamics

    Homework Statement Hello, I was doing a dynamics question, but my answer didn't match the answer key. I want to see if I am wrong, or the book is. The answer in the book is 2100 N. Question: You are helping a friend move, and you need to load a 265 kg box of books. You slide the box up a ramp...
  22. UMath1

    Bicycle Translational Acceleration vs Angular Acceleration

    Homework Statement Given: Wheel radius is 20 CM, Gear radius is 5 CM, Coefficient of Static Friction is .2, Weight on rear wheel is 50 N. What is the minimum force that must be applied to the pedal for the wheel to begin accelerating on a level surface?Homework Equations Net T = I * a T = R X...
  23. S

    Virtual Work & Quadcopter Torques: Exploring Rotational Dynamics

    Here is what we know from virtual work: $$ \delta W=\sum_{i=1}^N{\vec F_i\cdot\delta\vec r_{i}} $$ Where ##N## is the number of bodies in the system. I am considering a quadcopter, modeled as a rigid body so it is just one body and we have: $$ \delta W=\vec F\cdot\delta\vec r $$ My question...
  24. I

    What Is the Maximum Acceleration of a 75g Object on a Spring?

    Homework Statement A 75g object vibrates at the end of a spring(k=5.0 N/M) if the maximum displacement of the object is 0/080m to tge right what is the maximum acceleration? Homework EquationsThe Attempt at a Solution Fs=-kx so... (-5)(0.080)=Fs and fs=fg so -0.4=75a then a is -.0053... the...
  25. H

    Chaos (Non-Linear Dynamics) Driven Damped Pendulum

    I want to investigate the phenomenon of Chaos in the form of how its driving amplitude affects _____, in a driven, damped pendulum, using a computer simulation given. Initially I was looking at 'degree of chaos' for the dependent variable - to measure this I wanted to use the Lyapunov...
  26. G

    Uniform circular motion with friction

    I recently took an exam in my engineering mechanics class and passed the exam except for one question. I have been trying to solve this question after the fact and determine the solution, however neither I nor several engineering tutors have had any success. The professor refuses to give...
  27. K

    Need assistance with orbital dynamics questions

    Hello, I am currently writing a novel and there are quite a few situations that I would like to create that involve orbital dynamics. I would like to be as realistic as possible. I am seeking a knowledgeable person that can ballpark these problems. I do not think that it would take to much of...
  28. B

    What Is the Second Derivative for Phi in Particle Kinematics?

    Homework Statement L=18ft , theta-dot=8rpm or .83776 rad/s, omega = 1 rad/s, fi-0=70.5 and fi-1=24 Homework Equations - 3D motion[/B]The Attempt at a Solution I have come up with a ton of different answet inbetween 12-18 ft/s^2. Non have been correct[/B]
  29. D

    Dynamics: Absolute and Relative Acceleration in Plane Motion

    Homework Statement A force P is applied to the rod which rests on a horizontal table. The following accelerations are produced. aA= 3.6m/s2 to the right, α of the rod = 6 rad/s2 CCW. Determine the acceleration of point G and B Homework Equations aG=aA+aG/A aG=aA+[(aG/A)tangential +...
  30. M

    MHB Exploring Conservation of Momentum in Fluid Dynamics

    Hey! :o I am looking at the conservation of momentum. The force at $W$ from the tensions at the boundary $\partial{W}$ is $$\overrightarrow{S}_{\partial{W}}=-\int_{\partial{W}}p \cdot \overrightarrow{n}dA=-\int_{W}\nabla p dV$$ where $p(\overrightarrow{x}, t)$ the pressure and...
  31. TomW17

    Very basic question on particle dynamics

    Homework Statement A car makes a left turn from a stopped position, increasing its speed at a rate of 2 m/s/s. If a book is on the dashboard of the car, at what time will the book begin to slide if the static coefficient of friction \mu_s = 0.3? The radius of the curve of the motion is 7m...
  32. LeDragonian

    How Is Displacement Solved in This Differential Equation?

    It has been a while since I was involved with my differential equations. I am a mech student. I was trying out a sample problem from the dynamics book and came upon this equation. k = some constant of proportionality for a spring pushing back a spring mounted slider. (1/k) arcsin(ks/v_0) = t...
  33. M

    What is the average power of the warmer bath in this thermal dynamics problem?

    Homework Statement A warm water bath containing 10.0L of water is connected to an ice-water bath with a piece of metal of length L = 2.11 m and cross sectional area A = 1975 cm2. The metal has a thermal conductivity of km = 60.5 Wm-1K-1, a specific heat of cm = 239.7 Jkg-1K-1 and a density of...
  34. N

    Reversible Carnot Cycle: Exploring Heat Dynamics & Conservation

    In a reversible carnot cycle the amount of heat added is always more than the amount of heat taken out. So why doesn't it explode? I'm wondering how heat is conserved mathematically as the area under the curve of a p-v diagram. u=q+w. If the heat during expansion is always more than the heat...
  35. T

    Gas Dynamic to Acoustic wave equation

    Homework Statement Derive from the formulas ##\frac{D^\pm}{Dt}(u \pm F) = 0## where ##\frac{D^\pm}{Dt} = \frac{\partial}{dt} + ( u \pm c) \frac{\partial}{\partial x}## the one-dimensional wave equation in the acoustical limit. \begin{cases} u << c\\ c \approx c0 = const\\ F =...
  36. M

    Mechanical principles rotating systems

    Homework Statement A shaft 2 m long rotates at 1500 revs min–1 between bearings as shown in FIGURE 2. The bearings experience forces of 5 kN and 3 kN acting in the same plane as shown. A single mass is to be used to balance the shaft, so that the reactions are zero. The mass is to be placed at...
  37. ManicPIxie

    Bernoulli, Fluid Dynamics, and ships

    Homework Statement The Plimsoll line is a line marked on the side all ships that effectively indicates the safe maximum load the ship can carry in that type of water at that temperature.You have been asked to stand on the dock and collect the tickets of the passengers boarding a cruise ship...
  38. M

    Dynamics: Collision with inclined plane

    Homework Statement I have two conceptual questions that I have written in read in my solution. The solution, and all the work, is correct. However there are two things that I am unsure as to why I am doing it. Thanks! Homework Equations Included in solution, although none should be needed as...
  39. X

    What exactly is moment, and when is it zero?

    I've been dealing with the concept of moment this whole year, in statics/dynamics but I've never really completely understood it, just rather memorized it. What I think moment is: If some point on a body has moment, then this means it wants to rotate. So moment is essentially what causes...
  40. J

    What Are the Best Fluid Mechanics Textbooks for Self-Study?

    Hello! My name is Josh Currently going into third year physics. My university does not offer a single course involving fluids except the most basic intro to bernoulli's equation. So, I thought I would make it my own project for the summer to learn some fundamentals. I was wondering if anyone...
  41. C

    Have You Calculated Mass Flow Rate Correctly in Fluid Dynamics?

    I've Attached the question and my answer to question 1 to task 3 and guidance if I've done it right? Or any guidance?
  42. X

    Is the tangential acceleration component always zero(wheel?)

    If a wheel is rolling down a hill without slipping then we know the contact point has zero velocity. Is it also true that the tangential acceleration of this point is zero too?
  43. E

    Carousel dynamics question involving collision need to check one part

    Homework Statement find the velocity that the man was traveling at immediately before the collision radius = 10m height = 3m angular velocity = constant mass of person = 65kg mass of kiosk = 150kg displacement of kiosk after collision = 5m coefficient of friction kiosk = 0.6 Homework...
  44. Nabil

    101 in air flow dynamics please?

    Hi everyone, I've got a newbie question which is probably more complex than I imagine so please bare with me. As a small DIY project I've trying to build a small exhaust filter system (A) for another device that produces undesirable fumes (B). I'm trying to work out if an axial fan (generates...
  45. D

    Simulation of small satellite dynamics in software

    Hello, First time poster in this forum. I am tasked with simulating small satellite dynamics in software this summer. I am new to this and am wondering how such a simulation is carried out. More specifically I am supposed to output the vector [ x y z xdot ydot zdot q1 q2 q3 q4 w1dot...
  46. ME_student

    Dynamics Question: Acceleration and Tension Calculation

    Homework Statement I feel like I've spent way too much time on this problem... So the given information is on the image along with all my work. I am finding the acceleration of the block and the tension in the cable. I know R is going to be the same in all the cords because the pulleys are mass...
  47. Z

    Conceptual Questions Regarding the Dynamics of Heat Transfer

    Homework Statement Three building materials, plasterboard [k = 0.30 J/(s m Co)], brick [k = 0.60 J/(s m Co)], and wood [k = 0.10 J/(s m Co)], are sandwiched together (as I've tried to show below). The temperatures at the inside and outside surfaces are 28.9°C and 0°C, respectively. Each...
  48. Feodalherren

    Rigid body dynamics: falling stick

    Homework Statement A stick of length L and mass m is falling on a table with kinetic friction uK and static friction uS. Find the equation that determines whether the rod will stick or slip. If m = 10kg and L = 100cm, uS = 0.8, uK = 0.7 and initial theta = 30 degrees find the initial accel for...
  49. J

    Dynamics Problem: Incline Block and Moment of Interia

    Homework Statement Homework Equations ∑F=ma ∑M=Iα 3. The Attempt at a Solution I used the dynamic equilibrium formulas to find the tension. The tension helps me to find the acceleration of the block. Then, I used kinematics to find the velocity. But, I'm not getting the right answer.correct...
  50. B

    Dynamics relative acceleration question

    Homework Statement Aircraft A is flying NorthWest at 800km/h. Aircraft B is flying in a circular, anticlockwise holding pattern, radius of 5km, at 400km/h.Show that the acceleration of A relative to B is A(A/B)= 2.469cosθBi+2.469sinθBj m/s2 Homework EquationsThe Attempt at a Solution I know...
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