Motion Definition and 999 Threads

  1. J

    Wave problem - when they meet given their equations of motion

    So what I did was made the two equations equal each other. A lot of stuff cancels out and I end up with x=-vt. My issue is that t isn't given and I am not entirely sure how to get it. I don't think taking the partitial derivative of time will be any help nor the partial derivative of...
  2. guest948

    Force and motion -- Person falling from 20m onto a cushion (EASY)

    APPROACH 1 (correct): Height above ground = 3 - (v+u)/2 * t = 3 - 18.263/2 * 0.25 = 0.717 m ----------------------------------------------------- APPROACH 2 (incorrect): Let d be the height from the ground when he is stopped by the cushion. PE loss = Work done against motion by cushion mgh =...
  3. H

    Oscillation of a particle on a parabolic surface [equation of motion]

    Hi, I have a particle on a parabolic surface $$y = Ax^2$$ and I have to show that the frequency is $$\omega = \sqrt{2Ag}$$ I don't know how to deal with a parabola. I don't think I can use the polar coordinates like a circle. I don't see how to start this problem and in which coordinates...
  4. S

    Projectile Motion: Using an arrow to shoot a coconut dropped by a monkey

    Let: ##x## = horizontal distance from person to tree ##h_t## = height where arrow hits the coconut (measured from ground) ##h_o## = height of monkey ##u## = initial speed of arrow ##\theta = 35^0## ##t = 1~ \text{s}## Vertical displacement of coconut until it is hit: $$h_t - h_o = -\frac{1}{2}...
  5. FEAnalyst

    Modeling impact forces in rotary motion

    Hi, how can I calculate the impact force in case when some object is in uniform circular motion and then suddenly hits the target. For example consider lawn mower's blade hitting stone or drum woodchipper's blade hitting branch. Both blades are already moving at full speed when they hit the...
  6. J

    Harmonic Motion Problem - Finding oscillation of charges in a circuit

    So since V(cap) + V(ind)=0 then Q/C + L dI/dt=0 Now since I=dQ/dt, I can replace dI/dt with d^2Q/dt^2 resulting in Q/C + L d^2Q/dt^2 =0 Now L d^2Q/dt^2 looks like a harmonic motion thing I can solve, where w^2=L. This means I can find w. I get 0.0005385. Now my issue is using this w gives the...
  7. J

    Harmonic Motion of a Mass between two springs

    So first I found the total energy of the system by calculating the potential Energy, Ep=0.5k(l^2+l^2) and get 2.0475 (this part is right). Then I find w using the period T=2pi/w, so w=2pi/1.21=5.1927 I also found the amplitude using E=1/2kA^2, so A=sqrt(2E/k)=0.212132 Now this is the part I...
  8. A

    Upward and downward movement of a rocket with the equation of motion

    Hello! I've done the following to solve this problem. a) Here I simply put in the time in the equation, s0 is = 0 and after that it was pretty much done $$s(t) = 42 *1 - \frac {9,81*1^2} {2} = 37,09m $$ b) Now here to see when the rocket reaches it maximum altitude and what height it is...
  9. mustafamistik

    Throwing Objects - Motion in Two Dimensions

    I stuck on part c and d. My attemption is attached.
  10. neilparker62

    Equations of Motion Revisited

    [url="https://www.physicsforums.com/insights/equations-of-motion-revisited/"]Continue reading...
  11. I

    A Bounded Packet Motion: Unravel the Asymptotically Helical Trajectory

    In the article 'Cellular vacuum' (Int. J. Theor. Phys. 21: 537-551, 1982), Minsky writes: "One can prove that any bounded packet which moves within a regular lattice must have an asymptotically helical trajectory.. . " He does not explain this statement further, nor does he give any references...
  12. I

    A Where Can I Find the Proof of Asymptotically Helical Trajectory in a Lattice?

    In the article 'Cellular vacuum' (Int. J. Theor. Phys. 21: 537-551, 1982), Minsky writes: "One can prove that any bounded packet which moves within a regular lattice must have an asymptotically helical trajectory...". But he gives no references whatsoever. I had no success in a search on the...
  13. sergiokapone

    Law of motion for orbiting particle in a uniform magnetic field.

    Hi all, I interested in how can I get low of motion in for orbiting particle in a uniform magnetic field $$\frac{d\vec{r}}{dt} = \vec{\omega}\times\vec{r},\qquad \vec{\omega} = \frac{e\vec{B}}{mc},$$ Of course, rotating about z' axis is very simple. \begin{equation}\label{eq:K}...
  14. Silverbeam

    Can an object maintain uniform motion without any external force?

    Hi, I’m new here and I signed up to ask for some help with a physics problem. I’m not trained, nor am I receiving training, in physics. I’m a bachelor of Geoscience student halfway through my course. The problem I have is with understanding and testing the law of uniform motion (I think that’s...
  15. chucho11028

    Motion in one dimension -- Experiments with a Hot Wheels car rolling down a ramp

    Hello This is not a homework, this is my own experiment to understand how the motion works. Please, follow my question here below: I have a hot wheels race with a slope with 10 degrees where I use a small car which departs from the top to the bottom. I have taken 5 times the time to get an...
  16. R

    MHB How Do You Solve Problems in Polar Coordinates?

    I need a little help with this problem please
  17. T

    Can PCA Be Used to Derive Equations of Motion?

    Was wondering if PCA can be used to find equation of motions, like F = kx.
  18. O

    Equation of motion of a marble moving on a generic vertical guide

    Hello to everyone :smile: I'd like to study this problem. You have a 2D guide, described by an equation y = y (x) in a reference interval x ∈ I = [a, b], placed in a cartesian vertical plane Oxy. The guide is frictionless and the only force that is acting is the gravity force. On this track, a...
  19. L

    Physics Graph Word Problem -- Motion of a person skiing down a slope

    I was able to do the first graph knowing that acceleration is 9.8 and my distance goes up by 10s (y-axis) and my time goes up by 1s (x-axis). For the other 3 graphs, I'm not sure where to begin because I don't know how to figure out my velocity
  20. kshitij

    Projectile Motion in 2D: Solving for Maximum Range in Inclined Planes

    I know the conventional method for solving this question using the formula for maximum range of a projectile in an inclined plane, but since it is an objective problem, if we consider a non general case where α=0, then clearly we can see that (see attachment) only one option matches which...
  21. Frabjous

    Classical Konopinski Classical Descriptions of Motion (1969)

    Does anyone have any experience with this book? It looks interesting. See attached TOC
  22. T

    Ball's motion after one bounce off the ground - SUVAT Question (ENGAA 2017)

    Please scroll-down to the end (Question 54): https://www.undergraduate.study.cam.ac.uk/files/publications/engineering_s1_qp_2017.pdf I have also been referring to unofficial worked solutions (http://www.engineeringadmissionsassessment.com/2017-solutions.html), but I didn't understand how it...
  23. Gonzalo Lopez

    Motion Equation for a magnet on a spring

    Apart from the trivial elements of the motion equation (m z'' = -kz -mg), I am required to find the force produced by the Eddy currents induced by the moving magnet. To do so, I calculated the magnetic flux through the hole plate: For a magnet: Bz=μo m 4π. 2z^2−r^2/(z^2+r^2)^5/2 so Φ = a→ +∞...
  24. cle102

    Uniform Circular Motion on a racetrack

    Not sure what I'm doing here. Not sure how to continue? Please help. Thank you in advance!
  25. cle102

    Uniform Circular Motion: banked race track circular path

    Basically, I need help to continue on this question. This is what I have now: Angle of the race track (angle of the grey part): tan(18/(169-108)) = 0.30396 Not sure how to continue?? What am I supposed to do and find next? Thank you in advance! :smile::blushing::oldbiggrin:
  26. E

    What is the physics behind line vortices and their equations of motion?

    I'm getting really stuck with understanding this example: (Source: page 98) What is a line vortex, and how do we derive those equations of motion? All I can tell is that the velocity of a given vortex depends on a contribution from every other vortex in the plane, but I wondered if someone...
  27. L

    Proportionality theorem and projectile motion

    So i have this question. If a projectile is fired from a spring loaded system and when it goes pass a chronograph, reads 300FPS and has a mass of 0.12grams. Is there any way to use the proportionality theorem (1/3=x/6 example) to approximate how fast a mass of 0.25grams is when fired from same...
  28. Daniel Boy

    Motion Equations by Newton's Formalism for a Double Pendulum

    By Lagrange's formalism, the motion equations for double pendulum are: Using Newton's formalism I can't obtain the second equation. Anyone can help?
  29. R

    Relative Motion Comparing my motion vs an airplane

    I'm having trouble understanding the plane one This is what I understand so far v I'm sitting at a chair right now and if I compare my relative motion to the ground my relative velocity would be 0m/s but if I compare my motion to the solar system I would be moving very fast. I just can't grasp...
  30. J

    I Time Dilation & Superluminal Travel: 2 Questions

    Two quick questions on time dilation and superluminal travel for a situation in which two people are in motion with respect to each other. 1) If Jack is moving with respect to Jill, Jill sees Jack's clock move more slowly relative to her clock, so Jill perceives Jack aging more slowly relative...
  31. kuruman

    How to Master Projectile Motion Without Quadratics

    [url="https://www.physicsforums.com/insights/how-to-master-projectile-motion-without-quadratics/"]Continue reading...
  32. J

    Exploring Motion in Physics: Beyond Translation, Rotation, and Oscillation

    In high school I learned about three kinds of motion in classical mechanics - translation, rotation, and oscillation. Are there any other kinds of motion in the physical world?
  33. S

    Converting State Vectors to Keplerian Orbital Elements for Binary Objects

    Homework Statement:: I'm working on a personal project to convert objects from a simulation using state vectors for position and velocity to Keplerian orbital elements (semimajor axis, eccentricity, argument of periapsis, etc.). However, the equations I am using do not calculate the...
  34. Leo Liu

    Planetary motion in a viscous medium

    The answer to (c) is ##-2\pi AGMm##. Answer to (d) For sub-question d, I used a different approach and I don't know why the solution to (d) is an appropriate approximation. What I did was that I use Newton's laws to obtain two differential equation in polar coordinate, as shown: $$\text{Assume...
  35. vintagelover007

    Fermi Motion of Nucleons due to a Beam of Neutrinos

    Stable nuclei have radii that are approximately given by the formula: R = r0_A^1/3 Where r0 = 1.25 × 10−15m and A is the atomic mass number. In many experiments of interest to modern particle physics, beams of neutrinos scatter from nucleons within the nucleus. Even though the nucleus is at...
  36. J

    Engineering Equations of Motion for Beginners: Simple Solutions

    I am beginner. Can anybody do that? I need solution. Thanks so much!
  37. iVenky

    I Are quantum computers required to be cold to reduce Brownian motion?

    I understand that based on what I have read online quantum computers are required to be close to absolute zero because it introduces less error. Is it because brownian motion due to thermal agitation of molecules reduces with temperature?
  38. N

    What is the Correct Equation for Velocity on a Curved Surface?

    Here's my solution: I've tried to find the equation of vx. But the graph that it is generating is not right. I am not able to figure out what is wrong in the equation for vx. Please let me know where is the equation wrong and what is wrong? Here's the graph:
  39. greedygnome

    Using Physics to explain the motion of Olympic Divers

    I have a feeling that they will reach the water surface in the same time. How do I explain this in physics?
  40. G Cooke

    Questions About Highly Coupled Magnetic Resonance

    This is one of very few in-depth sources of information I can find online about Highly Coupled Magnetic Resonance...
  41. aatari

    Finding the Uncertainty in the motion of a pendulum

    Hi guys can someone look at my work for uncertainty and let me know if it makes sense.
  42. B

    Is a Crash Inevitable Given the Conditions Described?

    1. I'm trying to calculate the time at which the crash does not happen (if possible, because I don't know the official solution. I assume the crash is preventable). At the time t the truck decelerates and makes the distance ##s_2= \frac{v_2^2}{2a}##. In the same time the car drives with the...
  43. A

    Motion of a rocket with propellant exhaust gas speed = constant

    Now this is how I've tried to solve this $$ v_e = u0 \cdot ln \frac {M} {M- μ \cdot t} $$ After putting in the values I get this; $$ v_e = 200 * ln 0,36 $$ $$ v_e = 73,54 \frac m s $$ Now I'd say that this is the correct way to do it, but this part is confusing me "What is the speed of the...
  44. J

    I Zeno's paradoxes of motion in physics

    if zeno's paradoxes are true and motion is impossible, then how does an electron reach the electrostatic field of another electron?
  45. Andrei0408

    Uniformly accelerated linear motion downwards

    Could you check if what I did is right and help me at e) and f)? Thank you!
  46. F

    Motion of particles close to the Earth

    I tried to solve the problem in 2 ways, first using lagrangian mechanics and second by putting a rotating reference frame on the initial take-off point. However I cannot be sure if the equations of motion for the two solutions came out the same. A-) Equations of motion from Lagrangian...
  47. J

    Special Relativity - relative motion of two bars

    Hi, I'm stucked in this exercise. I don't know how to proceed. Any hints I appreciate it.Two bars of the same proper length L, moves in the same way on the x axis. In the referential of one of the bars the time interval between the events, when the extremity right of one bar and the extremity...
  48. Andrei0408

    Understanding Exercise 3 and 8 in Freefall and Motion Law

    I need help with the exercises attached in the pictures. Basically, exercise 3 is already solved but I need some help understanding every subpoint (for example, at a) how did we get to 0=H -g* tAO/2 , I know it's from the motion law and vA=0, but why is y(t)=0?). And I tried solving ex 8, but I...
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