Dynamics Definition and 1000 Threads

General Dynamics Corporation (GD) is an American publicly traded, aerospace and defense corporation headquartered in Reston, Virginia. As of 2020, it was the third-largest defense contractor in the United States, and the third-largest in the world, by sales. The company is a Fortune 100 company, and was ranked No. 83 in 2020.Formed in 1954 with the merger of submarine manufacturer Electric Boat and aircraft manufacturer Canadair, the corporation today consists of ten subsidiary companies with operations in 45 countries. The company’s products include Gulfstream business jets, Virginia- and Columbia-class nuclear-powered submarines, Arleigh Burke-class guided-missile destroyers, M1 Abrams tanks and Stryker armored fighting vehicles.
In 2020, General Dynamics had worldwide sales of $37.9 billion and a workforce of more than 100,000 full-time employees. The current chairman and chief executive officer (CEO) is Phebe Novakovic.

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  1. Shankar Das

    Practicing Mechanical Engineering Dynamics Problems

    Hello, I hope you all are doing fine and healthy. For my mechanical engineering dynamics I want to practice related problems taught in my class, here is a preview of some problems. Can anyone tell me from which book or solution manual are these problems from? I want to practice as much problems...
  2. A

    What is the Residual in Computational Fluid Dynamics?

    Can someone please tell me a basic and easy-to-understand example of Residual in CFD? Thank you
  3. jedishrfu

    News Some of My Friends Having Fun (Boston Dynamics Doing the Twist)

  4. K

    Which Program for Drawing Statics & Dynamics Mechanicals and Setting Dimensions?

    Wich The Program (Software) Using To Draw Statics And Dynamics Mechanichal Same This 100% When Create This below Which Program Using ? And set Dimensions Thanks For All
  5. Rzbs

    I Semiclassical model of electron dynamics

    Why do we exclude interband transitions in semiclassical model of electton dynamics? I mean why it is an assumption in this model?
  6. ezfzx

    Ball rolling within a rolling cylinder

    Cylinders rolling down inclines are a common demo. But how do you model the movement of a sphere rolling within a rolling cylinder? I teaching a physics class and this question came up and my dynamics math is a little rusty. But I haven't found anything like this in any book or online. There's...
  7. E

    Two rotating masses balanced by a third mass (rotational dynamics)

    Here's a diagram of what the system looks like: So far I have figured out what the initial angular velocity is, if the system is balanced (no movement): ## \sum F_m = m*\frac{v^2}{R_0}-\frac{Mg}{2}=0 ## ##m \frac{v^2}{R_0}-\frac{Mg}{2}=0 ## divide both sides by m ##\omega_0 =...
  8. yecko

    Why is ro = 0.2255 in fluid dynamics vortices?

    why is ro = 0.2255? Thank you
  9. T

    Calculating air resistance for a cart rolling down a ramp

    I am doing a physics lab where we are supposed to calculate air resistance and find the impacts of velocity and cross sectional area on air resistance. For the experiment, we rolled a cart down a ramp and measured data using Pasco Capstone software. When rolling the cart down the ramp, we...
  10. T

    Rotational Dynamics - Modeling brake caliper deceleration of a chassis

    I am a junior engineer tasked with modeling the dynamics of a small research UAV after landing. The UAV has 3 tires, 1 on the nose landing gear and 2 on the rear landing gear. The rear tires are equipped with disc brake calipers. My coworker has explained that the simplified model (MODEL 1...
  11. thaiqi

    I Exploring Dynamics of Electron in Hydrogen Atom

    Hello,everyone. Can dynamical system be used to describe the behavior of the electron in Hydrogen atom?
  12. A

    Dynamics problem involving an inclined plane and Friction

    So after trying to calculate the horizontal forces to solve it: f + Wx(gravity force component of x) - Fy ( the Force that is supposedly giving the the acceleration) = 0 It got to me that the question said "plane has the acceleration" is that even possible? Unless the plane is another object...
  13. wcjy

    Rotational dynamics and the conservation of energy

    I = Icm + mr^2 I = 0.5 mr^2 + mr^2 I= 3/2 mr^2 By COE, mgh = 0.5(3/2 mr^2)(w^2) g(2r) = 3/4(r^2)(w^2) 8g/3 = rw^2 = v^2 / r v = sqrt( 8gr/3) v=0.511m/s ans: v=0.79m/s
  14. wcjy

    Rotational dynamics: Resolving forces

    Resolving the weight of the cylinder c, i get Mgcosθ (-y) and Mgsinθ (-x) mgsinθ - Fs - T = ma ---(1) (where Fs is frictional force and T is tension) τ = I α (where τ is torque and α is angular acceleration) torque is produced by both tension and frictional force (T-Fs) * r = 0.5 m r^2 α...
  15. fingerprintregion

    Relativity: Relativistic Kinematics and Dynamics

    I’ve read Beiser’s Modern Physics Chapter 1 and I am able to grasp the general theories but not so much when applying it to problems. I major in Chemistry and would really appreciate any head start/help/suggestions. For number 1 I thought of using L = L0 sqrt 1-v^2/c^2 but can’t seem to find the...
  16. T

    Has Interprocess Communication Been Used for Multi-Phase Macroscopic Analyses?

    I am aware that a lot of software exists to conduct such multi-phase macroscopic analyses. But has anyone ever used the tools of interprocess communication to do this? Consider, for example, these three: A Finite element code (For deformation) on a parallel machine A Dynamcis code (for...
  17. Adesh

    (I.E. Irodov problem 1.72) Dynamics problem involving a pulley

    . First thing that I notice is that the other part of string (to which body 2 is connected) is fixed. Therefore, I concluded that the body 2 is stationary with respect to the pulley 2 (let's agree that pulley to which body 1 is connected is pulley 1 and in same way pulley 2 is defined)...
  18. Adesh

    What's my mistake in this problem in dynamics involving pulleys?

    Find the acceleration of block A and B, given that the mass of pulleys and strings are negligible.. I could see that the block B has gravity acting on it, therefore the gravitational force on the block ##B## is ##F_B = 5 g## and hence the acceleration is ##g##. From the pulley to which...
  19. T

    Solar System Dynamics page at NASA/JPL

    Stumbled across this and found it interesting. Solar System Dynamics pages at JPL (Jet Propulsion Lab)/NASA. Has Bodies, Orbits, Physical Data, Tools, etc. https://ssd.jpl.nasa.gov/?site_map Cheers, Tom
  20. A

    A Spin dynamics and the Pauli exclusion principle

    For high temperature superconductivity, people usually say two quasifree electrons are pairing, one is spin up and the other one is spin down. So, if that is the case, each two electrons will have zero spin angular momentum. Since the superconductivity is the magnetic properties and spin is the...
  21. Tymofei

    Pressure Differential in Fluid Dynamics: Why More on the '+s' Side?

    Here i added a page from my fluid dynamics book where it shows particle model for deriving the equation. My question is why pressure is more at stream side aka 'positive "s" direction'.I would expected more pressure on the other side because for example when you trying to push a rigid object or...
  22. Tymofei

    Calculating the Moment from a Different Vantage Point

    Summary:: Just a simple 3d rigid dynamics question which I am trying to solve by placing coordinat system differently from original solution.Everything looks ok but results are different. Mod note: Post moved from technical section. Thats my question.As you see coordinate system was located...
  23. Serhatakguc0

    Dynamics homework -- Motion of a stick attached to a rolling disk

    Hi everyone, I need help for this homework. I'm a mechatronics engineering student and i want to solve this question but no matter how hard I try, I can't solve the question. Sorry for my bad english...The disk connected to the AB stick with a length of 2 meters is rolled as shown in the figure...
  24. A

    Stabilizer Leg Linear Actuator Force to Jack up a Truck's rear tyres

    Hi, I previously posted about the statically indeterminate truck problem. Thank you to everyone who helped me. However, I now realized that isn't the problem I need to solve. I need to know the force of the linear actuators to lift the rear tyres off the ground. Since the tyres will be...
  25. E

    Orbital dynamics math review for a computer simulation

    The program begins by prompting the user to input the initial angle and speed. Once these values have been input, the program calculates the initial velocity components for the asteroid in two dimensions. printf("Input an initial angle from 10 to 80 degrees\n"); scanf("%f", &theta)...
  26. M

    Engineering Help with Dynamics Please -- Projectile fired downward into a fluid medium

  27. M

    Computational Fluid Dynamics and refining the mesh

    Hi PF! I'm running a two-phase simulation, which takes a long time to run. The simulation is simply a partially filled tank being drained in zero gravity, and the tank is a little smaller than a mailbox (~ 160 X 40 X 40 mm). Before running the simulation I would like to know if my mesh is...
  28. Adesh

    An isolated object can rotate only about its center of mass

    I was talking to someone about the equilibrium of fluids and we reached at some stage where we had to prove that in an external field the translational forces add to zero along with moments (torques) should also add to zero. The first one was quite easy but during the discussion of second...
  29. D

    Fluid dynamics and incompressible fluids

    Hi sorry about the way I've posted I'm new to this site. Anyway basically I've been set this question which should be attached to this post, I have attempted to do this question but I'm having trouble in forming an equation in the first place. I'm unsure where to start, I understand I need to...
  30. Helena Durrant

    Problem involving friction, with a mass being pulled up a slope

    (The answer from the markscheme is 26.7)
  31. SianRR

    Motion in Electric and Magnetic Fields -- (Uni Level Dynamics)

    I've attached my attempt at a solution below, I thought integrating it would be the best way to go but I'm just getting so confused and could use some help. This isn't my first attempt at a solution either I've been working on this for just under two hours now.
  32. T

    Integrating FE and Dynamics

    (CAVEAT: I am on the verge of retiring. And as I look back on my life, I realize how much I do not know. And I am using the convenience of time, now, to go back and ask the questions I always wanted to understand. So, please forgive me for these questions. They have always been my mind and I...
  33. S

    Periodic Boundaries in Molecular Dynamics Simulations

    In molecular dynamics people use periodic boundaries to confine particles being simulated. I read here that they are used to simulate large "infinite" particle systems. How can I know that the periodic boundary is simulating actual molecular outcomes for a finite particle system that had a large...
  34. A

    A Visualizing water molecular dynamics in an electromagnetic field

    I am interested in showing a visualization of water molecules in a time-varying electric/magnetic field as part of my PhD work. I would like something like this visualization: , but with an external time-varying field applied. At first, I thought of simply animating water molecules...
  35. tamim94

    How Do You Calculate the Acceleration of a Box on Banked Wheels?

    A homogen box with the mass M rolls without sliding on two round wheels. The wheels with mass mass m are also homogen and roll without sliding, on top of the banked Surface. We use Gravitation g. Find the accelration xM of the box I don't know which solution is correct. i got 0.67 m for xM...
  36. H

    Accurate Fluid Dynamics By Video Analysis

    Continue reading...
  37. Nacho_rc11

    Rotational dynamics: Rotating rod with two attached balls about a non principal axis

    Firstly I deduced that in this situation the moment of inertia I, is not going to be parallel to w. And I calculated it as a matter of the angle, for the rod and the two point particles attached (with a mass 'm'), and the total moment of Inertia ended up being: I=((R²*sin²α)/2)*(M/6 + m) Being...
  38. A

    Solving the Constrained Lagrangian Dynamics equation for a simple pendulum

    The equations is of the form of Differential algebraic Equation, of index 3.
  39. T

    A Lagrangian to the Euler-Lagrange equation

    Hello all, I understand the formation of the Lagrangian is: Kinetic Energy minus the potential energy. (I realize one cannot prove this: it is a "principle" and it provides a verifiable equation of motion. Moving on... One inserts the Lagrangian into the form of the "Action" and minimizes it...
  40. minadd

    Find all forces & the coeff. static friction of a pulley at equilibrium

    Given: (block a) m = .500kg (block b) m = .200kg that's all... Fg (block a) = (.5)(9.81) = 4.905N = Fn Fg (block b) = (.2)(9.81) = 1.962N i think acceleration might go like... a = (1.962)/(.5 + .2) = 2.8m/s^2 but isn't it supposed to be at equilibrium? So 0m/s^2. How am I supposed to find...
  41. L

    B Structure and Dynamics of Blue Supergiants

    There seems be much understanding of the internal structure the Sun for instance its several layers,thecore, the radiative and convections zones, the corona and so forth. What is known about stars that are not like the Sun? I was particularly thinking blue or red super giants.
  42. nuclearfireball_42

    Help with a pulley problem with 3 masses

    The figure : What I understand from the figure : T1=m1a1 T2=m2a2 T3-m3g=m3(-a3) - The three masses given all have different mass so each of them has different acceleration - How do one substitute to obtain the answer for a3? - I've tried to substitute to find the value of a3, but it seems...
  43. BigDumDum

    Fluid Dynamics and Global Warming

    Almost 90% of all humanity lives in the Northern hemisphere. Due to colonization, expansion, growth, war, water sources, etc. we have amassed our populations in specific areas around the Northern hemisphere. We continue to build at an unprecedented rate. Our buildings are growing wider, taller...
  44. Like Tony Stark

    Finding angular velocity for a rope to be cut

    I wrote Newton's equations for each body (I took ##x## as the axis aligned with the tension) ##m_1##: ##x)f*_1 -T_1+T_2=0## Where ##f*_1=\omega ^2 r_1## ##m_2## ##x)f*_2 -T_2=0## ##x)f*_2=T_2## Where ##f*_2=\omega ^2 r_2## I wrote that ##T_2=1100 N## and solved for ##\omega##, and I got...
  45. Like Tony Stark

    Is the Normal Force on m2 Affected by Vertical Acceleration in Different Cases?

    I want you to tell me if I'm right For 1), does ##m_2## feel a normal force? Because I don't think so, since it isn't pushing the wall. For 2), ##m_2## suffers a normal force because it feels a pseudo-force to the left and so it pushes the wall
  46. L

    Atwood System - max. height of the lighter object

    Magnitude of acceleration of system: a = (4.59kg - 1.71kg)(9.81N/kg)/(4.59kg + 1.71kg) = 4.48 m/s^2 Velocity of lighter mass when heavier one hits the ground: vf^2 = vi^2 + 2ad = 0 + 2(4.48m/s^2)(2.60m) vf = 4.83 m/s [up] I am not sure what to do from here? I don't really understand what...
  47. Like Tony Stark

    Finding the angular velocity of a rotating arm

    A) The slider experiments three forces, all of them are on the ##x## axis (considering ##x## axis as the axis aligned with the arm): Normal force (exerted by the support), elastic force and centrifugal force, which is ##m.(\omega^2 r)## Elastic force is equal to ##Fe=-k \delta =-2 (R-2R)=2R##...
  48. Like Tony Stark

    Find the tensions acting in different ropes that conect three bodies

    I called the smallest body ##1## and the biggest ##3##. All of them are disturbed by horizontal forces. So the free body diagrams are For ##1## ##-T_1 -Fr_1 +F=10a## For ##2## ##T_1 -T_2 -Fr_2=20a## For ##3## ##T_2 -Fr_3=30a## Then, if I consider ##a=0## and I solve for ##1## I get ##T_1=30...
  49. Like Tony Stark

    Acceleration and tension of a block on an inclined plane

    I considered the downwards direction and left direction as negative. For ##m_1##, Newton's equations are: ##x) Fr + W_x - T=0## ##y) N - W_y =0## For ##m_2##: ##y) T - W =0## Then, if I replace the data, I get ##T=22.2 N## and then ##m_2=2.2 kg##. With that, for the second question ##m_2=4.4...
  50. Like Tony Stark

    Forces acting on a block which is lying on another block

    Well, I'm having trouble with the free body diagrams. For ##A## we have ##y)## weight, normal force, contact force with ##B##, ##F . sin(36.8°)##. And the acceleration is ##0## because we want to calculate the maximun force before moving. ##\Sigma \vec F = m . a_y## ##\vec N_A + \vec F ...
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