What is Dynamics: Definition and 1000 Discussions

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. rocdoc

    Dirac's Generalized Hamiltonian Dynamics Theory?

    I wondered if anyone might know of any open access materials, possibly lecture notes, on the content of the following papers or books. P.A.M Dirac, 1950, Can. J. Math. 2,147 "Generalized Hamiltonian Dynamics" P.A.M Dirac, 1933, Proc. Camb. Phil. Soc., 29, 389 "Homogenous variables in classical...
  2. K

    Finding the radius of the sphere

    Homework Statement In a spherical bowl a small ball is jumping around. The ball hits the bowl in two spots and moves in two different trajectories in times T1, T2. Find the radius of the bowl. Homework Equations Newton's laws of dynamics. The Attempt at a Solution The only thing I could...
  3. S

    Schools I want to focus on Fluid and/or soft body dynamics

    Hi, I finished my first Bachelor in Physics, than continued my studies by finishing second bachelor in mechanical engineering. I am a very enthusiastic pilot, maybe that's the reason why I'm pulled towards fluid dynamics and soft body dynamics. Well my dilemma is the following: I don't know...
  4. F

    Origin and demonstration of Newton's second law

    At high school, we saw without demonstration the fundamental principle of dynamics (2th Newton's law), i.e : $$\sum \vec{F}=m \vec{a}\,\,\,\,\,\,\,\,\,eq(1)$$ after, at university, we saw another expression of this 2th Newton's law : $$\sum \vec{F}= \dfrac{d\vec{p}}{dt}\,\,\,\,\...
  5. K

    Block-pulley system and rotational dynamics

    Homework Statement Two blocks, m1 = 1.0 kg and m2 = 2.0 kg are connected by a light string as shown in the figure. If the radius of the pulley is 1.0 m and its moment of inertia is of the system is 5.0 kg*m^2, the acceleration of the system is (expressed as a fraction of gravitational...
  6. jamalkoiyess

    Classical Swarm Dynamics Introductory Book

    I am searching for a good book that could be used as an introduction to the dynamics of swarms and maybe their self organization. I am a physics junior and would like something that is decent for that level.
  7. chrononaut 114

    Past Exam Advanced Dynamics Question; Help, Please

    Homework Statement The Attempt at a SolutionSo I first tried by saying consider a time t in which mass m is directly above the origin O. I.e., mass m at the Cartesian coordinate (0, 4l/3). I wrote a = a(t) as the extension function of the spring, which has 0 natural length. So, I applied the...
  8. |Glitch|

    I Action Dynamics of the Local Supercluster

    The interactive model can be found at: Action Dynamics of the Local Supercluster Interactive Model Source: Action Dynamics of the Local Supercluster - The Astrophysical Journal, Volume 850, Number 2, December 2017 (free preprint)
  9. M

    Newton's Third Law: Acceleration of box and worker

    Homework Statement On a horizontal frictionless floor, a worker of weight 0.900 kN pushes horizontally with a force of 0.200 kN on a box weighing 1.80 kN. As a result of this push, which statement could be true? A ) The box will not move because the push is less than its weight. B ) The worker...
  10. D

    Dynamics: Spring problem (Oscillation)

    Homework Statement The mass m = 4 kg and the spring constant k = 64 N/m. The spring is unstretched when x = 0. At t = 0, x = 0 and the mass has a velocity of 2 m/s down the inclined surface. What is the value of x at t = 0.8 s? The angle of incline is 20 degrees, and with the mass moving down...
  11. A

    Rotational Dynamics of a Grindstone

    Homework Statement A grindstone is used to sharpen knives and consists of a stone cylinder and a central axle There are bearings between the axle and the frame to reduce any friction. This grindstone has a mass of 60 kg, a diameter of 0.600 m and has a moment of Inertia (I) of 4.50 kg.m2 ...
  12. E

    Molecular Dynamics Simulation - How Do You Find Parameters?

    Hi all, I'm doing a bit of material science research at my university. I'm running molecular dynamics simulation programs like Lammps and Amber as part of it, and I'm pretty new to the whole thing (just like I'm pretty new to this forum). I'd like to ask, has anyone here used Amber to find their...
  13. W

    Comparing Generalised Momentum Calculations for Central Force Problems

    Homework Statement I have an issue with understanding the idea of generalised momentum for the Lagrangian. For a central force problem, the Lagrangian is given by, $$L = \frac{1}{2}m(\dot{r} ^2 + p^2 \dot{\phi ^2}) - U(r)$$ with ##r## being radial distance. The angular momentum is then...
  14. bob012345

    Dynamics of Lorentz force on a current carrying wire

    Hello all, I've been pondering a problem with a current carrying wire in a magnetic field. The Lorentz force is easy, ILB, with a velocity 90 degrees to the B field. So let the force accelerate the wire. Assume only one segment of the wire that has current in one direction, say up, is in the...
  15. JTC

    Difference between Hamiltonian and Lagrangian Mechanics

    Hello, I am trying to "integrate into my understanding" the difference between Hamiltonian and Lagrangian mechanics. In a nutshell: If Lagrange did all the work and formulated L = T - V, they why is Hamilton's name attached to the minimization principle? YES; I KNOW about Hamilton's Second...
  16. S

    Rotating Bodies Around Origin: Analyzing Motion & Dynamics

    Homework Statement Hello! I have 2 bodies initially at rest, of equal masses with the distance between them a and coordinates ##(a cos(\theta),a sin(\theta))## and ##(-a cos(\theta),-a sin(\theta))##. If we denote ##a_x## and ##a_y## the horizontal and vertical distance between them they...
  17. Javier Mont

    About moving through the air and Newton´s 3rd law

    How are we able to move trough the aire if the air exerts a force equal to the friction we use to push us through air? I´ve had this problem in my mind since some days now. I did this picture: url: https://www.kn3.net/60DAC45480AJPG.html
  18. P

    Fluid Dynamics -- a spherical particle immersed in water

    Homework Statement Consider a spherical particle immersed in water. It will experience random collisions with the surrounding water molecules. Suppose there are such water molecules around the particle. Half (n/2) of the water molecules will push the particle to the right and the other half to...
  19. S

    What is 'phase space in chaos theory and nonlinear dynamics?

    The term 'phase space' is often used in the study of nonlinear dynamics.What is it.
  20. S

    How Do You Calculate Velocity and Acceleration from a Position Vector?

    Homework Statement The position vector of an object of mass 0.10 kg at time t in seconds is given by =(^3+5)−4+2^2 Find the velocity and the acceleration as a function of t Homework Equations =(^3+5)−4+2^2 The Attempt at a Solution For velocity I think the equation needs to be...
  21. A

    B Telescope and Stopwatch for the Mass of a Planet

    I was wondering if it is possible to use only a stopwatch and a telescope to find the mass of a planet, such as Saturn. I've experimented with a couple of things but I keep running into problems. I previously asked this question in the homework section, but it does not involve numbers, is not...
  22. J

    Dynamics and Circular Motion Problem

    Homework Statement A 2 kg tetherball swings around a vertical pole attached to two ropes each at a 30 degree angle from vertical. Each supporting rope is 1.5 meters long, and the ball travels at 8 m/s long. Homework Equations The question doesn't ask what they're looking for, so I assume they...
  23. F

    Acceleration along a pulley with a ledge

    Homework Statement Homework Equations F = ma The Attempt at a Solution The solution to the problem is 1.12m/s^2. However, I don't know how they got to that number. Every way I do it I end up with 3.2m/s^2.
  24. M

    Find the tension in the cable and the force the ramp exerts on the tires

    Homework Statement A 5000 kg car rests on a 32° slanted ramp attached to a trailer. Only a cable running from the trailer to the car prevents the car from rolling off the ramp (the car's transmission is in neutral and its brakes are off). Find the tension in the cable and the force that the...
  25. D

    Determining Coefficient of Friction for Two Boxes with Applied Force

    Homework Statement Suppose there are 2 boxes over a horizontal surface. One has mass M and the other one has mass m. The one with mass m is over M as shown in the picture and a horizontal force is applied to pull M. There is no friction between M and the surface, but there is friction between m...
  26. M

    Forces and Free-Body Diagrams in Real-World Scenarios

    Homework Statement I am just going over my class notes and I just wanted to clear up a few concepts regarding forces and free-body diagrams -- I'm either missing some forces or adding one too many: Identify the forces acting on objects in each of the following situations and draw a free-body...
  27. A

    Gravitational force acting between objects

    Homework Statement 4 10kg objects are located at the corners of a rectangle sides 2 meters and 1 meter. Calculate the magnitude of gravitational force on 1 due to the other 3. (Same sort of idea) 3 1kg objects are located at the corners of an equilateral triangle of side length 1 meter...
  28. A

    Newton's 3rd Law Dynamics Problem

    Homework Statement A 12.0-kg box is pushed along a horizontal surface by a 24-N force as illustrated in the diagram. The frictional force (kinetic) acting on the object is 6.0 N A) What is the acceleration of the object B) Calculate the value of the normal force acting on the object C) If the...
  29. A

    B What is the Net Force on a Banked Curve?

    I understand why when deriving the formulas for cars on banked curves, the net force in the Y direction is zero. However, when I google how to derive them, people say that there is a net force greater than zero in the X direction. This is not what my professor says in his explanations however...
  30. R

    Rigid body relative acceleration

    Homework Statement Rigid body (ship) rotate and moves around 3 axis (x,y,z) around the center of gravity. The position is of the center of gravity is not known. What is known: At a point (A) the accereleration, velocity and position and rotational acceleration, velocity and position are known...
  31. J

    How do I calculate the mass of a moving object?

    Homework Statement Someone mistakenly threw away a lovely couch, and you decide to take it back to your apartment. You push it with a force of 350 Newtons and at 30 degrees below the horizontal at 2 m/s. The coefficents of friction are μs = 0.4 and μf = 0.3. What is the couch's mass? Homework...
  32. P

    How Does a Nucleus's Mass Change After Emitting a Gamma-Ray Photon?

    Homework Statement A stationary excited nucleus decays to its grpund state by emitting a γ-ray photon of energy Eγ. The grpund state nucleus recoils in the opposite direction at speed v. Show that when v<<c the change of mass of the nucleus is approximately: me - mg = Eγ/c2 [1+ 1/2(v/c)]...
  33. A

    What is happening in this fluid dynamics problem and how can we approach it?

    Homework Statement Problem: https://imgur.com/a/ppDy6 Calculate the fluid speed at a certain point Given fluid and sound speed before the point Length of the conduct 2. Useful Equations: Uniformly accelerated motion(my solution) I have been studying this problem it for some time, have...
  34. Z

    Finding the acceleration in a curvilinear motion (n-t)

    Homework Statement The mine skip is being hauled to the surface over the curved track by the cable wound around the 38-in. drum, which turns at the constant clockwise speed of 96 rev/min. The shape of the track is designed so that y = x2/28, where x and y are in feet. Calculate the magnitude of...
  35. Adrian59

    A Galaxy dynamics explained without DM or MOND

    I have been working on a discovery that could explain galaxy rotation curve without dark matter or modification of Newtonian dynamics. However, I was unable to make any comment within this forum since this was unpublished work. However, the same discovery has been made independently by Kenneth F...
  36. G

    Fluid dynamics: simulation of an oil system

    Good day folks! I am working on the simulation of an engine, and in particular the oil system makes my head ache. I already finished the calculations for viscosity and temperature, but now I'm stuck on coming up with formulas for pressure and flow rates. With what should I start? For...
  37. M

    What are the best resources for studying astrophysical fluid dynamics?

    i am an aerospace engineer and have good knowledge in fluid and gas dynamics and i want to study astrophysical fluid dynamics , should i study intro to astronomy and astrophysics ? and what are best books in astrophysical fluid dynamics ?
  38. mkematt96

    Dynamic Shear Force on a Brake Pad

    I'm looking for a way to calculate the shear force applied to a brake pad from stopping ( a small engine brake pad stopping a fly wheel). I know shear stress is shear stress/ area , would this apply for a dynamic application as well? Would I need to calculate the force to stop the flywheel at a...
  39. JTC

    A Split the differential and differential forms

    In undergraduate dynamics, they do things like this: -------------------- v = ds/dt a = dv/dt Then, from this, they construct: a ds = v dv And they use that to solve some problems. -------------------- Now I have read that it is NOT wise to treat the derivative like a fraction: it obliterates...
  40. K

    Dynamics of a point mass in circular motion

    Homework Statement Dear All, I'm having a hard time solving the following problem: A point of mass is moving on a circular plane (Oxy), where the circle's formula is: The force acting on mass "m" is defined as: We're looking for velocity of point "m" in position (1,1) =V1, and in position...
  41. G

    Confused about tension in strings

    Hello! I'm just having trouble understanding the logic about tension in strings. m = 5[kg] v = 2.8 [m/s] g = 10 [m/(s^2)] String in massless and air friction is negligible The question is what the tension in the string is when the ball is in the bottom position. My reasoning is that the...
  42. Alexanddros81

    Pytels Dynamics 12.40: The rocket sled is propelled....

    Homework Statement The 13-kN rocket sled is propelled along a straight test track. The rocket engine fires for 4 seconds, producing a propulsive force of F=5.3kN, and then shuts down. Assuming that the sled starts from rest and that the coefficient of kinetic friction is 0.05, determine the...
  43. Alexanddros81

    Calculating Height h from a Projectile Launched at A

    Homework Statement A projectile launched at A with an initial velocity of 24 m/s at the angle θ=60deg, impacts the vertical wall at B. Neglecting air resistance, calculate the height h Homework EquationsThe Attempt at a Solution Here is my solution As you can see to find height h I assumed...
  44. C

    Is my Rolling Body Mechanics Solution Correct?

    Homework Statement In the picture ,problem 8.29 Homework Equations Energy conservation ,velocity relation ,momentum The Attempt at a Solution First i defined the speed of the body relative to the ground as Vb and speed of plane relative to the ground as Vp. From momentum ,VbcosΘ=-Vp .From the...
  45. Alexanddros81

    Pytels Dynamics 12.39: A rocket is launched vertically

    Homework Statement A 2000-kg is launched vertically from the surface of the earth. The engine shuts off after providing a constant propulsive force of 60 kN for the first 20 seconds. Neglect the reduction in the mass of the rocket due to the burning of the fuel and the variation of the...
  46. B

    TFD (topological fluid dynamics) matricial form

    Homework Statement Using the matricial form of TFD (discret Fourier Transform) calculated : X=Fd(x) for x=(1,0,2j,1-j)^T from K^4 Homework Equations X=wx The Attempt at a Solution I know the "x" matrix and the "w" matrix but i don't know how to find the "ω" variable from the "w" matrix...
  47. K

    Can yaw motion still occur in a quadcopter in vacuum?

    So I recently developed an interest in quad-rotors and was getting stated with its dynamics. I am particularly intrigued by the yaw motion of a quad-copter which comes into effect as a result of torques of the motors. When the motor torques are variable, we observe the yaw motion as result of a...
  48. B

    Dynamics ramp and friction. Finding angle?

    Homework Statement A 3.0 kg block is released from the top of a rough ramp of length 2.0m and accelerates down the ramp at 1.6m/s^2. If a force of kinetic friction of 10 N acts on the block, what is the angle of the ramp. Homework Equations Fnet=ma ff=(mu? I don't have that symbol HAHA) muFn...
  49. Alexanddros81

    Pytels Dynamics 12.35: A cart carrying a small package

    Homework Statement The cart carrying the small 9-N package A is moving up the incline with constant acceleration α. If the package stays at rest relative to the cart in the position θ=45deg, determine the value of α. Neglect friction. Homework EquationsThe Attempt at a Solution [/B] Are my...
  50. C

    Compressing a bottle with water - initial velocity of water

    Imagine that we have a closed plastic bottle filled with water and then we punch a hole with area A in its cap. How can I find the initial velocity the water will he "fired" with if we squeeze the bottle applying stress S? Assume that we know all about the bottle (moduli, change in volume etc...
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