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. vilasini

    Closed trajectory of a wormhole

    Homework Statement I have a metric for wormhole. Now if I want to find the closed trajectory for this metric how will I proceed from here? Help me with detailed maths if possible. Homework EquationsThe Attempt at a Solution
  2. Abhishek11235

    Trajectory of a particle under the given force

    A particle of mass m in xy plane is attracted toward the origin with the force $$\begin{align}\vec{f} = - \frac{k^{2} m}{r^{6}}\vec{r}\end{align}$$ where ##\vec r## is position vector of particle measured from origin. If it starts at position ##(a,0)## with speed $$v=\frac{k}{\sqrt{2} a^{2}}$$...
  3. C

    Trajectory of a proton as it moves between the plates

    Homework Statement Homework Equations What makes the shape circular/ parabolic? what determines the direction? The Attempt at a Solution Because the furthermost plate is positive, the proton would be repelled towards the screen, so i or iii. How do I know the shape?
  4. PKM

    How to find the Trajectory of a Particle

    Homework Statement The velocity of a particle at a certain point is given as \vec v=5(y\hat i - x\hat j). How to find the general equation of the path of the particle? Homework Equations Here, \frac{d\vec x}{dt}=5(y\hat i - x\hat j). The Attempt at a Solution As the velocity is not given as a...
  5. Arman777

    Python Verlet algorithm and Lorentz force trajectory

    I need to write a code to calculate the trajectory of the particle under lorentz force.Since the position depended equations are hard to solve I ll use a code, how can I appraoch this problem. I should use veloctiy-verlet algorithm or any suggestions ? You should consider that lorentz force is a...
  6. D

    I Why do rockets turn horizontally so soon after launch?

    My 12 year old asked me this question. I have a MS in Mechanical Engineering, so I can usually answer his physics questions, but this one stumped me. When lifting off, why do most rockets turn close to horizontal almost immediately? Of course we know they need mostly horizontal speed to...
  7. F

    The trajectory of an electron and a proton between two charged sheets

    Homework Statement Homework Equations - The Attempt at a Solution (A) , because the proton moves in a direction opposite to the electron. Right ?
  8. Francis Perez

    Find the Initial Velocity and Launch Angle for a Particular Trajectory

    Homework Statement Hello, so I’ve been trying to find some possible way to calculate this: The initial Velocity and angle needed to launch a projectile and reach the coordinates (x,y). The maximum height the ball can reach before it starts to head down to the target value should be y+5m The...
  9. S

    I Calculate Voyager trajectory using JPL data

    Hey everyone, I've recently programmed an animated simulation of the main elements (core planets and Sun) of our solar system: by using the initial coordinates from the JPL database, and then calculating the combined gravitational perturbations and the relativistic effects from the Sun...
  10. M

    "Trajectory" question for my novel

    I am in the midst of penning a novel and need help with a physical analogy. I've scoured google for an answer and, perhaps because I have a headache right now, my eyeballs are swimming. So, I figured I should come here and ask. An object (in this case, a person's career) is on a trajectory...
  11. Phantoful

    Optimal Trajectory Angle for Maximum Area?

    Homework Statement A ball is thrown at an initial speed v from level ground. What angle θ should be chosen so that the area under the trajectory is maximized? Homework Equations d = Vot - (1/2)gt2 Vt = d Integration, derivatives, and trigonometry The Attempt at a Solution I've tried to find an...
  12. T

    Trajectory of a Projectile that must clear an obstruction

    I am trying to solve for Vy with given Vx. I know how to do this for the BLUE trajectory line, but I do not know how to solve this if there is an obstruction in the way (like the gray wall). My givens are: X1 X2 Y1 Y2 Vx Gravity Do I need to solve for the blue trajectory then adjust that for...
  13. Victoria_235

    Kinematics problem -- Calculating acceleration from the trajectory

    Homework Statement For each of the following cases, represent on the trajectory, the velocity and tangential and normal components of the acceleration at times t1 and t2 of a mobile that moves according to the graph of s (arc) versus t (time) on the left. The point O on the trajectory marks the...
  14. kandelabr

    Trajectory with minimum acceleration

    Currently design of turbomachinery (impellers/turbines) is more a form of art than an engineering process. One has to guess a bunch of parameters and check if they are right in much later stages of design. I was thinking about designing the other way: we know the initial and the final velocity...
  15. Rednecknav

    I Calculating Energy to Remove Space Debris from Earth Orbit

    How much energy needs to be be expended to throw a non operating satellite (or other space trash) out of orbit (L4 or L5) or L2 into deeper space... thus minimizing space debris in Earth orbit. I could only find formulas for getting an object INTO orbit... Background of question: we were...
  16. V

    Calculating the trajectory of an object into a force field

    How can I calculate the trajectory of an object knowing the initial conditions and the function F(x,y)? For example, a object orbiting a planet or two electric charges orbiting each other.
  17. P

    I Computational physics - Light trajectory near black hole

    Dear all, I am currently doing a project about the light trajectory near Schwarzschild black hole. I wrote down a couple of differential equation and I have created a C++ program hoping to solve the orbit of light. However, the program results turn out to be quite weird. The differential...
  18. mertcan

    Photoelectric effect -- direction of the electron's trajectory

    Hi, I would like express that I really tried to dig something about the formula related to electron direction in photoelectric effect, but I could not find. Also I have seen that electron direction in photoelectric effect is not known according to some sites in internet. So, ıs it real that in...
  19. T

    Exploring Trajectories Near a Point: Smooth Curves or Sharp Edges?

    Suppose a particle is moving in an X-Y plane. It's velocity in X direction will be dx/dt and in Y direction will be dy/dt. Suppose at a certain point it's velocity in x direction is zero and in y direction is also zero. Then, dx/dt =0 & dy/dt =0 at that point. Now, what will the trajectory be...
  20. lfdahl

    MHB Particle Motion in a Vertical Plane: Trajectory Equation & Curve

    A particle moves in a vertical plane from rest under the influence of gravity and a force perpendicular to and proportional to its velocity. Obtain the equation of the trajectory, and identify the curve.
  21. B

    Velocities when generating an Archimedean spiral trajectory

    hey, I just want to know, if I am to send a velocity commands to generate a spiral trajectory, What would be these velocities (angular and linear)?? Thanks in advance
  22. Z

    I Why not calculate the "trajectory" of a wave function

    The classic limit of Schrodinger equation is hamilton-jacobi eqution. Wave function's classic limit is ##\exp{\frac{i}{\hbar}S(x,t)}##,##S(x,t)## is the action satisfying hamilton-jaccobi eqution. However, a particle travels along single trajectory of ##S(x,t)##, Why not make some constrains...
  23. Pushoam

    What is the radius of the circular arc in a sine curve trajectory?

    Homework Statement Homework EquationsThe Attempt at a Solution Every small part of the trajectory can be taken as a circular arc. Then, $$\frac { m v^2} R ≤ kmg $$ But how to find out R from the sine-curve?
  24. Pushoam

    Projectile motion, radii of trajectory

    Homework Statement Homework EquationsThe Attempt at a Solution For part (d), The curvature radius of trajectory at its 1) initial point = horizontal range/2 =( v02 sin (2α))/2g 2) peak = height of ascent/2 = ( v0 sinα)2 /2g Is this correct? In this problem, the time of ascent is equal...
  25. H

    Equation for Brownian Motion Trajectory

    I am trying to understand how one can simulate the trajectory of a Brownian particle as a function of time. I am only able to do it with the assumption that I can simply generate random values of x and then take the cumulative sums of these values to get the trajectory of the Brownian particle...
  26. donaldparida

    Bullet trajectory: Aiming a gun

    Homework Statement : [/B]A person aims a gun at a bird from a point at a horizontal distance of 100m. If the gun can impart a speed of 500m/s to the bullet , then above what height of the bird he should aim his gun to hit it ? Homework Equations : [/B] H_{max}=\frac{u^2\sin^2\theta}{2g}...
  27. person123

    Is my equation for projectile trajectory accurate?

    I derived an equation for the trajectory of a projectile. Given the height and distance of the projectile, and the initial velocity, it determines the initial angle. When plugging it into desmos, it seemed to make sense (https://www.desmos.com/calculator/pfylvs4tau), but I still can't be sure...
  28. T

    Momentum -- pure rolling and trajectory physics problem

    Homework Statement Two solid spheres one of mass 'm' and other of mass '2m' are comin towards each other(translationally) with a velocity v1 and v2.After collision the sphere of mass 2m comes to rest and the sphere of mass m does oblique projectile motion at an angle 30 with the vertical till...
  29. Dusty912

    Radius of curvature of trajectory

    Homework Statement a golfer hits a golf ball so that it has an initial velocity of 165mph and 12 degrees above the horizon. I already know the radius of curvature when the ball is hit. but my question is, will the radius be that same when it hits the ground? Homework Equations an=v2/ρ The...
  30. peasqueeze

    Modified Cycloid motion of charged particle

    I need a charged particle trajectory in crossed E and B that is a cycloid in the x-y plane. This part is simple enough, but I want the trajectory to be parabolic in the x-z plane. The images will help explain what I need. The left image shows the shape I want to achieve, and the right image...
  31. S

    My ballistic trajectory on the Moon looks wrong

    Hi all, I'm writing a science fiction story and I have managed to confuse myself. I have a rail line that accelerates a train in Tycho crater and tosses a heavy payload of ore to Descartes, about 1200 km, where it's supposed to land on another ramp... or something. I've used Google Earth to...
  32. NoahCygnus

    Projectile motion: equal distances in 5th and 6th seconds of trajectory

    Homework Statement With what speed should a body be thrown upward so the distance traversed in the 5th second and 6th second are equal? Homework Equations No idea since I fail to comprehend the statement of the problem. The Attempt at a Solution This doesn't make sense to me, the distance...
  33. I

    I Name for electron's trajectory outside of the orbit?

    I wonder if this question will make sense, but I will do my best shot: As the electron orbits around the nucleus, I imagine there are moments when it is too far away, so it starts to be "pulled toward" the nucleus. If it gets too close, it will be "pushed away". If it is in the orbital area...
  34. T

    Proton trajectory grazing a charged sphere

    Homework Statement Homework Equations potential energy = -kQq/r potenial = kQ/rThe Attempt at a Solution i am not quite sure how does l play a part in this experiment since it is far away l is insignificant and the only initial energy is kinetic energy and final is kinetic and electric...
  35. R

    Trajectory of a particle in a spinning fluid

    Homework Statement I need to show that a particle suspended on a spinning liquid (which is spinning with constant angular velocity) describes a spiral . (I need to solve this without using Lagrangian-Hamiltonian formalism)Homework Equations [/B] Weight and Bouyant forceThe Attempt at a...
  36. DeldotB

    Consistent Trajectory for a non-zero rest mass particle?

    Homework Statement Good day all! Quick question: As part of a problem statement, I'm asked to verify if the trajectory: \frac{dx}{dt}=\frac{cgt}{\sqrt{1+g^2t^2}} Is "consistent". Homework Equations None The Attempt at a Solution Im not sure what "consistent" means. Does it mean, \frac...
  37. Q

    What is the trajectory of a projectile and how is it related to parabolas?

    Homework Statement I won't be able to provide the specific problem (in terms of numbers). I was hoping for a conceptual solution. A ball is thrown. From its initial location, it lands on a shelf a given distance away. I am given the distance to the shelf, the height of the shelf, and the...
  38. learis

    B Trajectory of photon or electron in double slit

    Hello, first post. I recently became interested in quantum physics and its mysteries. To my understanding, In the double slit experiment, the photon or electron will scatter and behave like a wave when both slits are open and neither slit is measured. Over time their cumulative scattering mimics...
  39. Z

    Meaning of trajectory in four-electricity in Landau's book

    Homework Statement I think the in equation ##(28.2)##,##x^i## in ##\frac{dx^i}{dt}## and the ##x^i## decides ##\rho## is not the same,if they are equaivalent,##\rho## can not vary with position changing and time fixed, because ##\frac{dx^i}{dt}## indicate the ##x^i(t)## which means if position...
  40. farolero

    Is the trajectory parabolic or elliptical?

    Parabolic shooting is a kind of orbit interrupted by the ground. So I was wondering if I could calculate speeds of the bullet accounting for conservation of angular momentum. Would this diagram be correct?
  41. doktorwho

    Finding the radius of curvature of trajectory

    Homework Statement The functions are given: ##r(t)=pe^{kt}## ##\theta (t)=kt## ##v(r)=\sqrt2kr## ##a(t)=2k^2r## Find the radius of the curvature of the trajectory in the function of ##r## Homework Equations $$R=\frac{(\dot x^2 + \dot y^2)^{3/2}}{(\dot x\ddot y - \ddot x\dot y)}$$ There is also...
  42. doktorwho

    Solving for the trajectory in the polar coordinate system

    Homework Statement On the surface of a river at ##t=0## there is a boat 1 (point ##F_0##) at a distance ##r_0## from the point ##O## (the coordinate beginning) which is on the right side of the coast (picture uploaded below). A line ##OF_0## makes an angle ##θ_0=10°## with the ##x-axis## whose...
  43. P

    Satellite Orbit Trajectory and Velocity Doubling: Parabolic or Hyperbolic?

    Homework Statement A satellite moves in an elliptic orbit with eccentricity e=1/2 around a planet which it was launched. When it arrives at an apsis( a radial turning point), its velocity is suddenly doubled. Show that the new orbit will be either parabolic or hyperbolic depending on which of...
  44. Q

    Kinematics - trajectory formula

    Homework Statement given : i need to find the trajectory formula Homework Equations i'm not sure if to use : The Attempt at a Solution [/B] I tried different options with the trigonometric identities that I have written before: thanks
  45. A

    Kinematics: Understanding Trajectory Equations

    Hi, Just starting to learn kinematics and the book says that from the kinematic equations of motion: x=ƒ1(t) ; y=ƒ2(t) ; z=ƒ3(t) we can "eliminate de time" from the above and get: F1(x,y,z)=0 ; F2(x,y,z)=0 -> aka. trajectory eq. their "ensemble" being 2 surfaces giving the trajectory...
  46. J

    What is known about helical flight paths in bullets?

    I have a physics degree, I'm now retired and have taken up long range shooting as a hobby. When shooting at 600 yards, my spotters have noticed the contrail of my bullet follows a helical trajectory near the target. I shoot a 243 (6mm), 105 grain target bullet made by Berger at a muzzle...
  47. Cocoleia

    How to find trajectory as a function of time with energy

    Homework Statement I am given that an object of mass m has an attractive force F=-A/x^2 acting on it, where A is a constant and x>0. I need to find the potential energy. After i need to suppose initial conditions (x0, v0) such that total energy=0. I need to find the trajectory x(t) with v>0...
  48. L

    Ball trajectory velocity and displacement vectors

    Homework Statement ball is thrown at slighta angle upwards and to the right. Angle between horizontal and the launch velocity vector is 35deg upwards. Launch velocity vector (v_0) has magnitude of 12m/s Only gravity affects the ball as a force. (no air resistance) t_0 = 0 secs t_1 = 0.2 secs...
  49. S

    Tracing object trajectory through a photocamera

    Hi all, I need to trace the trajectory of a moving object. The object are yellow and opaque while the background is grey. Since I'm interested in the shape rather than the exact coordinate, I'm wondering if I could use the light painting principle to impress on a photo the trajectory. How could...
  50. AlenC

    B Simulating orbit trajectory based on position and velocity

    Hi! I hope I'm posting in the correct section. I found this very similar topic in this forum: https://www.physicsforums.com/threads/orbital-ellipse.482713/ Aside from very helpful formula for calculating semi-major axis, the question was left unanswered. I have a working simulation of...
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