What is Trajectories: Definition and 127 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. P

    Billiards - Predicting Optimal Trajectories?

    Is there a program code or game or applet that will allow me to predict.. basically, the initial and standard state of the table. Say, I give it initial positions. Given the angle and magnitude of the cue ball, it should tell me what the final positions of each balls are. Which brings me to...
  2. M

    Writing Equations of Particle Trajectories in Proper Time

    Homework Statement I have the trajectories of a particle in the space-time: \tau(\sigma) = \frac{1}{a}senh(\sigma) x(\sigma) = \frac{1}{a}cosh(\sigma) How can I write this equations depending on proper time t of the particle? Homework Equations The Attempt at a...
  3. E

    Lorenz Attractors and Trajectories

    Homework Statement I'm using the textbook "Nonlinear Dynamics and Chaos" by Strogratz. So far, it's been terrific. However, I got to the section on the Lorenz attractor and got stuck. The author has a picture and an explanation that eludes me. The picture in question can be seen on this...
  4. Z

    Does Asymmetry in Spacecraft Flyby Trajectories Cause Unexpected Energy Gains?

    It has been found that spacecraft on certain flyby trajectories around the Earth gain an amount of energy that is unaccounted for. The asymmetric trajectories highlight this anomaly as described here http://en.wikipedia.org/wiki/Flyby_anomaly" . I read that the most asymmetric flyby’s...
  5. N

    Are parabolic trajectories really accurate for objects in motion?

    Parabolic trajectories ? When you throw an object into the air, fire a cannon ball etc. we assume the trajectory to be that of a parabola, but it is in fact an elliptical path (IGNORING WIND RESISTANCE) Think about it (ignore wind resistance), we assume that the lateral velocity is unchanging...
  6. O

    Bohmian surreal trajectories

    Bohmian "surreal" trajectories Hi guys... I have read most of bohmian argument and critics about it here. But unfortunately, I'm an economist, have not a physics B.A.! I want to ask stg., I'll be grateful if you answer... I read Englert's argument (ESSW paper) and also replies... But...
  7. A

    Regge Trajectories: What Are They?

    what are regge trajectories?
  8. B

    What are the Conditions for a Massive and Massless Particle in Spacetime?

    Homework Statement The equations of motion are: \frac{d^2 x^\mu}{d\tau ^2} = 0 Write down the tra jectory that’s the most general solution to them. What are the conditions on your solution if the particle is: (a) Massive? (b) Massless? The Attempt at a Solution I am not...
  9. P

    What Equations Are Used in Projectile Motion Calculations?

    hi, can some one help me with projectile??its a general question..what are the equations do we use to do a sum with projectile??to find velocity??maximum height??and other stuff.. please help me as soon as possible...
  10. B

    Ind the orthogonal trajectories of the family of curves

    Homework Statement Find the orthogonal trajectories of the family of curves. Use a graphing device to draw several members of each family on a common screen. y = x/(1+kx) 2. The attempt at a solution I have been trying this problem for hours, and I get a different answer every time...
  11. M

    Elliptic trajectories of the electron

    I would like to give me some information about elliptic trajectories of a free electron around a proton? THNX in advance
  12. D

    Family of orthogonal trajectories for a vertical parabola

    1. Homework Statement . The correct answer is E 2. Homework Equations :Procedure from our text: "Step 1. Determine the differential equation for the given family F(x, y,C) = 0. Step 2. Replace y' in that equation by −1/y'; the resulting equation is the differential equation for the family of...
  13. 6

    Dynamics: solve both trajectories

    Hey all, Having trouble solving this one. Class is dynamics. 2D, constant accel. Shooting a cannon at a point above the initial. Inital velocity is 400m/s Cannon is at point A (origin) and we're shooting at point B @ (5000m, 1500m) I'm asked to find the two thetas that satisfy...
  14. L

    Trajectories of motion of bugs

    Hello! I'm thinking about the following problem at the moment: Four bugs sitting at the corners of the unit square begin to chase one another with constant speed, each maintaining the course in the direction of the one pursued. Describe the trajectories of their motions. What is the law of...
  15. W

    Vectors and Trajectories, help with problems

    just a few similar problems. 38- A ball is rolled off a table with an initial speed of 0.24 m/s. A stop watch measures the ball's trajectory time from the table to the floor to be 0.3 s. What is the height of the table? (neglect air resistance) a. 0.11m b. 0.22m c. 0.33m d. 0.44m I think...
  16. A

    Kepler orbital trajectories and 'effective potential'

    Ok so the total energy of a body following a given trajectory around a much larger body (eg. Earth and sun), is described by : E(total) = (1/2)mv^2 + U (where U = grav. potential energy) E(total) = (1/2)mv^2 - (GMm)/r (1/2)mv^2 can then be expanded to give : E(total)...
  17. G

    How Would a U-Boat Captain Calculate the Angle to Fire a Torpedo at a Tanker?

    Say in World War II a u-boat captain is trying to sink a tanker. He knows the distance to the tanker, its speed and heading (which are assumed to be constant) and the speed of the u-boats torpedos. How would he calculate what angle to fire the torpedo to hit the tanker?? (Assuming the u-boat...
  18. E

    Why are regge trajectories of hadrons opposite to classical physics?

    OK the very origin of string theory is based on the observations of the regge trajectories pert. to hadrons. Funnily enough you get the relation that the ang. mom. is directly proporitional to the square of the energy (if i remember correctly) which would not be the case if we were dealing with...
  19. W

    Possible trajectories under central force and

    Hi we just studied motion under central force. we got the following question... is this possible trajectory(see attachment) under central force and force source is outside the loop? (my answer is that it is possible if force source is repulsive) whatever the answer is how can i explain it...
  20. M

    2 Things: Work-Energy theorem and parabolic trajectories.

    Hi, When reading through the work-energy thread, i just got reminded of something bugging me for quite a while. I don't think this is mentioned in the work-energy thread, firstly, how can we show that, \int f \bullet ds = \Delta E also, I've heard that there's a way to show that...
  21. T

    Projectile Trajectories: Finding Optimal Firing Angles and Flight Times

    I have a problem. So far, I have decided that this problem is using the Range Equation. Here it is - The initial speed of a cannon ball is 200m/s. If it is fired at a target that is at a horizontal distance of 2 km from the cannon, find A) the two projected angels that will result in the hit and...
  22. E

    Can complex potentials lead to allowed trajectories?

    let be the solution to SE in the form \psi=exp(iS/\hbar) where S has the "exact" differential equation solution in the form: \frac{dS}{dt}+\frac{1}{2m}(\nabla{S})^{2}+V(x)-\frac{i\hbar}{2m}(\nabla^{2}{S}) then we could form the complex potential:U=V(x)-\frac{i\hbar}{2m}(\nabla^{2}{S})...
  23. B

    Needing help with projectile trajectories

    I've been working on making a package of Java classes to use in developing programs/games using actual physics instead of 'best guess'. The problem is I'm pretty rusty with the whole subject, and am lost trying to get a formula for projectile trajectory with air resistance taken into account...
  24. RadiationX

    What are the orthogonal trajectories for x^2y=c_1 and x^2+c_{1}y^3=1?

    find the orthogonal trajectories of the following (a) x^2y=c_1 (b) x^2+c_{1}y^3=1 for part (a) I've found y=\frac{1}{2}\log{|x|} + C_2 for part (b) if i solve this integral this should be the O.T. \frac{3}{2}\int{(\frac{1}{x^2}-1)}dx= \frac{y^2}{2} is this correct?
  25. M

    Solving Orthogonal Trajectories of a Family of Curves

    Here is the problem: Determine the orthogonal trajectories of the given family of curves. y = \sqrt{2\ln{|x|}+C} This is what I've done so far: y = (2\ln{|x|}+C)^\frac{-1}{2} y' = -1/2(2\ln{|x|+C)(2/x) Now I understand to find the orthogonal lines I need to divide -1 by...
  26. Loren Booda

    Gravitational vs electromagnetic quantum trajectories

    Consider a hydrogen atom, with orbitals describing movement of an electron about a proton, together bound by the electromagnetic force. Next consider an equivalent "atom" made up of two massive neutral particles, where the gravitational force at a given separation is the same as the Coulomb...
  27. M

    What Determines the Flight Time of Projectiles with the Same Horizontal Range?

    Two Projectiles are shot through the air, and we don't know the launch velocity or angles. What we DO know is that both projectiles cover the same horizontal range. What can be said about the flight time of each projectile? Air Res etc etc is ignored. Thanks in advance.
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