What is Trajectory: Definition and 461 Discussions

A trajectory or flight path is the path that an object with mass in motion follows through space as a function of time. In classical mechanics, a trajectory is defined by Hamiltonian mechanics via canonical coordinates; hence, a complete trajectory is defined by position and momentum, simultaneously.
The mass might be a projectile or a satellite. For example, it can be an orbit — the path of a planet, asteroid, or comet as it travels around a central mass.
In control theory, a trajectory is a time-ordered set of states of a dynamical system (see e.g. Poincaré map). In discrete mathematics, a trajectory is a sequence



(

f

k


(
x
)

)

k


N





{\displaystyle (f^{k}(x))_{k\in \mathbb {N} }}
of values calculated by the iterated application of a mapping



f


{\displaystyle f}
to an element



x


{\displaystyle x}
of its source.

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  1. S

    Proton enters magnetic field in spiral trajectory

    Homework Statement A proton moves in a spiral path when enters a magnetic field of 5 T. If the pitch is 5 cm, find the angle between v and B. Homework Equations F = B q v sin θ F = m v2 / r The Attempt at a Solution I am guessing that I need to break down the velocity into two...
  2. A

    Magnetic force Particle trajectory

    Homework Statement A particle of charge −q is moving with a velocity \vec{v}. It then enters midway between two plates where there exists a uniform magnetic field pointing into the page, as shown in attached image. (b) Compute the distance between the left end of the plate and where the...
  3. B

    Why does a stream change trajectory?

    Okay bear with me here because this might get disgusting. But I was watching Henry's video on how astronauts went to the bathroom in space, and basically they did it in a bag, and shot the bag outside into outerspace. And then he mentioned that the trajectory would change(but extremely small yet...
  4. S

    Trajectory of objects in imperfect conditions.

    I am familiar with standard distance-time models for paths of projectiles in perfect conditions, ie, where the curvature doesn't play a role, and where gravity is constant no matter the height. My question is what if you launch a projectile so high that the curvature of Earth plays a role, and...
  5. A

    Moving an object over predetermined trajectory

    Need some guidance on how to approach the following scenario Object : 200 grams movement axis : x, y, z distance : 20 meters speed : 70 to 150 kmph adjustable. The plan is to have 3 motors on a jig to control the movement on 3 axis. The issue is to reach 50 m/s speeds and...
  6. G

    How to show that a trajectory is closed?

    Main question in the title. I did a group work in analytic mechanics about pendulum in rotating reference frame and stumbled upon this one: http://peer.ccsd.cnrs.fr/docs/00/50/17/84/PDF/PEER_stage2_10.1016%252Fj.ijnonlinmec.2008.03.009.pdf. Does this always hold? In my solution, there are two...
  7. J

    Exploding shell at the top of its trajectory

    "After a shell explodes at the top of its trajectory, the center of gravity of the fragments has an acceleration, in the absence of air resistance, equal to g and downward." Why isn't there an x-component? I get why there would be a downward component with a = g, but shouldn't there at...
  8. A

    Trajectory function of projectile motion

    I've been studying this rather interesting article about projectile motion in special relativity. The thing is, I can't understand how the author found the trajectory function. He says that he did it by solving the following parametric equation: x(t)=\frac{cp_0cos\theta}{F}ln\left \{...
  9. 1

    What is the Radius of an Electron Trajectory in a Magnetic Field?

    Homework Statement Electrons (mass m, charge –e) are accelerated from rest through a potential difference V and are then deflected by a magnetic field B that is perpendicular to their velocity. Find the radius of the resulting electron trajectory. Homework Equations F=\dfrac{mv^2}{r} F=qvBThe...
  10. P

    Plot Trajectory of Particle - Get Help Now

    Hello, How may I plot the trajectory of a particle whose movement vectors are given as: x(t) = Rwt - Rsin(wt) y(t) = R - Rcos(wt) I have tried squaring both x and y and adding them, to infer some sort of circular trajectory, to no avail. Could someone please assist/make a suggestion?
  11. F

    Acceleration of a curved trajectory

    Feynman_Lectures_on_Physics_Volume_1_Chapter_11 In paragraph 11-6 he says that the tangent acceleration is the change of speed v but if I look at fig. 11-8 the change in speed is slightly smaller than the change in tangent velocity. (I drew a circle with the radius of the speed of v_I that...
  12. A

    A projectile exploding at the top of its trajectory

    Homework Statement An object is launched from the origin. At the peak of it's trajectory, it explodes into two fragments, one of mass m and the other of mass 3m. The smaller fragment of mass m lands back at the trajectory. How far from the origin does the second fragment land? Homework...
  13. P

    Analyzing the Trajectory and Acceleration of a Rocket Launch.

    Hello, Granted that a body begins accelerating from rest with a constant acceleration a, and after a certain time T changes the direction of its acceleration and begins moving with acceleration -a, would it be correct to say that the body would return to its origin at time t=2T? I mean, are...
  14. B

    Solving Complex Trajectory Puzzle: Find m's Path Equation

    Can anyone solve this puzzle for me - a mass m in space with a constant velocity C heads toward a circular mass M such that if not disturbed it would pass by M at a distance of 2 of M's radiuses. However, the mass m experiences a second velocity Ve towards the center of M; the magnitude of this...
  15. fluidistic

    Direction of trajectory, system of DE's and portrait phase in plane phase

    Hi guys! I had the following system of DE's to solve: \alpha '=-2i \alpha \beta ' =2i \beta. Where alpha and beta depend on t. I solved it by writing the system under matricial form, found the eigenvalues and corresponding eigenvectors. The solution is (and I've checked it, it works)...
  16. Adoniram

    Program to plot 3D trajectory?

    Howdy folks, I have been given the opportunity to do some extra credit for my mechanics class. As an assignment, my prof would like to see a 3D trajectory plotted via a program (like Python). My basic assignment is to plot the trajectory of a soccer ball after it has been kicked. I don't...
  17. S

    Trajectory of a horizontally fired projectile

    Homework Statement For a lab that we did I need to draw the path of a horizontally fired projectile using a graph. When I look at the equation I derived it doesn't look like it will draw the path correctly. The Attempt at a Solution Δx = Vox*t T = Δx / Vox -h = Voy*t + .5*a*t2 -h =...
  18. H

    Figuring Out Mysterious Meteorite: Speed, Trajectory & More

    Hello, I have figured out the basics so far, but perhaps someone could help me figure out a bit more. I observed this meteorite moving across the sky, looking like a low airplane glowing bright bright orange. from the american meteor site (http://www.amsmeteors.org/fireballs/faqf/#1), this...
  19. H

    Find where and when the trajectory angle is 10 degrees?

    Homework Statement Okay, this is a projectile motion problem(No Drag) where a rock is thrown as 35m/s at an angle of 48 degrees. The question that I am struggling with is: "Find where and when the trajectory angle is 10 degrees?" Homework Equations The Equation that my teacher was used...
  20. S

    Particle on a curved trajectory

    Hello Particle with nonzero mass moves on a curved trajectory. Why does it feel centrifugal gravity? Does spacetime curve or...? One answer might be that it feels gravity because the 1st law of Newton says so; but this wouldn't be good enough an answer :) Thank you
  21. G

    Orthogonal Trajectory. Calc IV.

    Homework Statement Find orthogonal trajectories for y=clnx, y=cex, y=sin(x)+cx Homework Equations Simple integration for the most part. The Attempt at a Solution I'm fairly confident on the first two, its the third that's giving me trouble. First, y=cln(x) c=\frac{y}{ln(x)}...
  22. C

    Need Help with trajectory based game equation

    Homework Statement i Pmed some mentors but they said i should post it at forum, i asked Astronuc that if its ok to post this in forum and he told me to post it in this section.. i know some users here are very senior and surely have the knowledge to this and i want to learn. it is a...
  23. F

    How do we decide if a trajectory is 1D, 2D or 3D?

    Hello Forum, In kinematics we study motion and the trajectories of moving bodies. The trajectory is a line (straight or curved) that joins all the positions occupied by the object in the various instants of time. A trajectory has an equation that contains only spatial coordinates (not...
  24. Q

    Calculating Ball Trajectory in Basketball Simulation Game

    So I'm making a little basketball simulation game and I need a good way to calculate the path of a ball. I want to do this on a frame by frame basis where one frame lasts about 50 milliseconds. Each frame will store values for the state of the ball and then after applying some math, those values...
  25. Q

    Derivation of area of trajectory of projectile

    Homework Statement This is a problem about an aircraft flying above a cannon which is capable of firing in any direction. The plane's height, velocity and the speed of the projectile fired by the cannon are given (I am not trying to get help in solving the problem, so the numbers are not...
  26. C

    Collision course trajectory / velocity

    Hello everyone! I have calculated the velocities required for an orbiting body to follow a circular, parabolic, and hyperbolic trajectory around another massive body, which are the following: v_{circular} = \sqrt{\frac{\mu}{r}} = \sqrt{\frac{GM}{r}} v_{parabolic} =...
  27. ferret_guy

    How to calculate trajectory of an object with air drag

    I am trying to predict the flight of an object with a parabolic trajectory including drag due to air resistance how do I do this? the wiki page was not clear its my understanding its relative to the square of the speed.
  28. M

    Fortran Fortran quassiclassical trajectory help

    Hello All, This is my first post on any forum so I will try not to get too fancy. I have been writing in fortran for about two months now and it is my first programming experience. First, I wrote a classical dynamics program for a particle moving toward a potential barrier. Then, I wrote a...
  29. K

    Having trouble finding trajectory of a small rocket

    Homework Statement So we launched small rockets on our last day, but have a week to turn in the homework based on the launch, but seeing as we aren't allowed back in school I can't ask questions I am lost. We haven't dealt with anything remotely related to trajectory since the beginning of...
  30. J

    Trajectory of charged particle in uniform gravitational potential

    It sounds like an easy-enough problem, but even writing down the ridiculously nonlinear equation that would need to be solved is making my face hurt. I'm talking classical/Newtonian gravitation, action-at-a-distance, constant-force. It could really be any external non-EM conserved force...
  31. MattRob

    Interplanetary Trajectory Calculation

    Hello, For something of a hobby of mine, I'm looking at different interplanetary trajectories for a Mars mission. I've got a somewhat interesting case; I only know basic calculus of a single variable (taken calculus 1), so I can't do the more in-depth multivariable and (I think) vector...
  32. 1

    Neutron Fission & Quantum Physics: How Does Gravity Affect Trajectory?

    just thinking cross sections here. a neutron that is freed as a result of a fission of pure U235. travels @c/10(fast!) will its trajectory be perturbed by the gravitational force emitted by a nearby nucleus, or do things on the quantum level work differently?
  33. A

    Calculating trajectory electric field

    In my class we have so far only dealt with electrostatics, i.e. fields of stationary charge distributions. However one question arose while doing so: Given a set of stationary source charges we can calculate the electric field at each point in space. But will that give us enough information to...
  34. A

    How can I calculate planet trajectory for a 2d solar system simulation?

    Hello. I am programming a 2d solar system simulation for a game. All went fine until I got to this part. Tried learning it in the past 3 days but could not understand most of it. Hoped to find help hhere. I have the location of both planets, their mass, their initial velocity and that's it. How...
  35. G

    Derive equation of trajectory of a body around a fixed body attracted by gravity

    Homework Statement There is a fixed spherical body of mass M whose center is to be taken as origin. Another body of mass m whose initial position vector \vec{r} is given. This body is projected with initial velocity \vec{v}. Find the equation of trajectory of body with mass m around the body...
  36. S

    3d trajectory of system of wheels

    Hello! I tried to develop equations of motion of system of wheels, where the first one with radius of r is rotated with some angular velocity v, the center of the second wheel is connected with the first on its perimeter and its plane of rotation is perpendicular to the plane of rotation of...
  37. S

    What Software Is Best for Simulating Particle Trajectories in 3D?

    Hi, I use a numerical method to trace trajectories of particles. I want to program a sort of 'video' type graph. A graph or 3d video or perhaps just 3 graphs (xy, xz, and yz) that would show the position of the ion as the software is run. So my question is this... What software would...
  38. T

    Patched Conics Trajectory from Initial Orbit State

    Hi, I've got a problem here, that I'd like to discuss before trying to implement any sort of solution. Basically I've got a planetarium simulation, in which I'd like to plot a patched conic trajectory ahead of a spacecraft . The planetarium only simulates two-body gravity, and switches...
  39. H

    Ball Acceleration and Trajectory Question

    Homework Statement A ball is dropped from a height of 39.0m. The wind is blowing horizontally and imparts a constant acceleration of 1.20 m/s^2 to the ball. a. Show that the path of the ball is a straight line and find the values of R and θ (R is the distance on the x-axis from the ball's...
  40. P

    Rolling Object on Curved Surface: Lagrangian Mechanics + Constraint

    Homework Statement I want to be able to plot a trajectory wrt time of a ball that rolls without slip on a curved surface. Known variables: -radius/mass/moment of inertia of the ball. -formula for the curvature of the path (quadratic) -formula relating path length and corresponding height...
  41. R

    The only trajectory problem on my whole SI sheet (trajectory) I cannot do

    Homework Statement This a trajectory problem. A ball is launched from ground level at a unknown angle. ( ∅o= ? ) at an unknown velocity ( Vo = ? ) The ball travels 20 meters in the x direction and 25 meters up in the y direction. At this point (20,25) the ball hits a wall and a -45 angle...
  42. P

    Solving trig problem for trajectory

    Need to find the angle at which a plane should aim if when traveling at 210km/h with a 40km wind east produces a resultant angle of 60 degrees. I can write that 60=tan^-1(210sin60/(210cos60+40) and proceed from there: tan60=210sinx/(210cosx+40) 1.73=210sinx/210cosx+40...
  43. J

    Developing a Softball Trajectory Model With Pneumatic Piston

    I am a hack at this, so I am turning to you guys for help. I need to develop a mathematical model do generate the speed of a softball when struck with differing amounts of force. The specs are: weight of ball 188g applied force 170 lb to 500 lb The force is applied by a...
  44. P

    Trajectory Path from 2 Distance Sensors

    I would like to determine the equation describing the trajectory of an object using data from 2 distance sensors. I figured out how to do this if the sensors take simultaneous measurements but this cannot be done without generating crass talk between the sensors. The object moves too far when...
  45. S

    Period of the DE trajectory

    I have a second order nonlinear ODE. I know that a trajectory with specified initial conditions \left[ x(0) = x_0, \dot{x}(0) = \dot{x}_0 \right] is periodic. How can I numerically calculate period of this trajectory without solve this DE?
  46. G

    How Does Igniting Fuel at the Trajectory's Apex Affect Missile Debris Dispersal?

    Homework Statement In testing a missile defense system, a missile is red from the ground on a trajectory that would directly hit a bunker some distance away. When the missile is at the top of the trajectory, a laser light from the bunker ignites fuel in the missile and the missile...
  47. C

    New memeber. ball trajectory puzzle

    hi there, new member and this is a bit off a puzzle to me (this isn't homework its something I am trying to use for a little simulation game haha) ok so the puzzle involves a ball being projected, i am wanting to find the minumum hight it can travell with the longest distance (does that make...
  48. E

    Amount of a magnetic force to alter the trajectory of a photon

    hello, I was just thinking since a photon trajectory is affected by a magnetic force.then I would like to know how much force does it take to do just so.
  49. T

    Archery trajectory computation

    Okay, this is not a homework problem, and I think if I really played with it long enough I could work something out. But really, I just want an answer, so I'm hoping someone on here who really loves solving problems like this can just knock it out. It would be much appreciated. I'm wondering...
  50. B

    Computing parabolic orbital trajectory

    I wrote a game with a rocket that orbits a planet, and you can change the orbit with thrusters. As part of it I draw the predicted orbit for the rocket. To do this I compute the eccentricity vector, then the eccentricity e, then the major and minor axis of the ellipse or hyperbola as...
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