Motion Definition and 999 Threads

  1. Krokodrile

    Superposition of two simple harmonic motion

    Hey! I am stuck in this problem, i don't know how to sum this ecuations. I remember that its possible because the direction is the same So, i try to sum like this: cos (t+5325) + 1.5 cos (t+5325) =1.5 cos (t+5325) I don't know if i fine. I thanks your help, please ;)
  2. A

    Damped Oscillatory Motion with Varying Bump Timing for Control

    First of all, the problem is not clearly defined as they don't specify if the given mass is the total mass of the car, or just the sprung mass of the car, which is really what's relevant. In any case, with the limited information given, it seems like one is forced to make the assumption that...
  3. V

    Would particle P be under non-unform circular motion?

    At t= 0, we can see that the particle P has a radial acceleration of ##-2\hat j## and a tangential acceleration of ##2 \hat i##. The radial acceleration will tend to move it in a circle of a certain radius, whereas the tangential acceleration will tend to displace it parallel to x- axis...
  4. Prez Cannady

    A Question about extragalactic stellar motion

    We have direct mass models of stellar motion inside of galaxies (basically, find a happy medium between a sphere and a disc). And of course dark matter corrections to explain the deviation between model and observation. Is there any pattern at all to the motion of extragalactic stars passing...
  5. P

    Equations of motion of damped oscillations due to kinetic friction

    Take rightwards as positive. There are 2 equations of motion, depending on whether ##\frac {dx} {dt} ## is positive or not. The 2 equations are: ##m\ddot x = -kx \pm \mu mg## My questions about this system: Is this SHM? Possible method to solve for equation of motion: - Solve the 2nd ODE...
  6. Krokodrile

    Is Your Calculation of Simple Harmonic Motion Accurate?

    The first ecuation values i am 99% that is correct. But, in the second and three problem i don't know if my results are ok. The problem number 2 i comprobate with the teacher that te aceleration its correct, so, with this i calculate the velocity. I use like example the second problem for try...
  7. Uchida

    Dynamics motion problem with a disk in contact with a bar

    First, I tried to model the disk-bar as a crank connecting rod, to the OA bar, and apply this: VP = VB + ω_BP x r_P/B, where P is the contact point between the disc and OA bar. I assumed VP = VP sin 30º i + VP cos 30º j (direction parallel to r_P/B), where r_P/B = sin 30º i + cos 30 j This...
  8. H

    Is My Thinking Reasonable: A's Impact on Oscillator Motion

    I just want to check if my thinking is reasonable. Since B,C and D are all dependent or fixed by the oscillator, A is the only factor to affect the amplitude of the motion at resonance or even throughout the entire process?
  9. brotherbobby

    Projectile motion with (constant) wind velocity

    Let me start be making a small sketch of the problem, shown to the right. If the range of the projectile on a still day ##R = v_{0x}T##, then on the windy day the range becomes ##R+2H = v'_{0x}T = (v_{0x}+v_w) T##. Since the maximum height attained by the projectile ##H =...
  10. C

    I Determining Future Position of Uniform Circular Motion

    Hello, Apologies if this is in the wrong section, it's related to circles so I figured Geometry was the best place. I found a very good example online that explains how to determine a future position of an object undergoing uniform circular motion: (Note that they made a mistake by writing...
  11. L

    A Heisenberg equation of motion -- Partial derivative question

    Heisenberg equation of motion for operators are given by i\hbar\frac{d\hat{A}}{dt}=i\hbar\frac{\partial \hat{A}}{\partial t}+[\hat{A},\hat{H}]. Almost always ##\frac{\partial \hat{A}}{\partial t}=0##. When that is not the case?
  12. ZdMh

    About difference in Velocity and motion in Jet engines

    I was watching a video about jet engines, and it was obvious for me and for the instructor that if we compress air at high speed from the gas turbine inlet, then after multiple stages collide with the turbines blades inside, the body will move in the sense of difference in velocity, so forward...
  13. Bob Enyart

    Is there any motion hidden within potential energy?

    Of potential and kinetic energy in their various forms, in their own reference frames, which involve motion? Heat, light, nuclear, kinetic, etc., seem to involve motion. Does potential energy, in any way whatsoever, involve motion? Thermal does. Does nuclear energy involve motion? Seems to...
  14. momoneedsphysicshelp

    Finding Angular Velocity in Rotational Motion Problems

    53 rpm equals 5.55 rad/sec multiply 5.55 by 2pi to get angular velocity of 34.8717 Is the answer 34.8717? What should I have done to more accurately solve the problem with a better understanding? What other steps should I take when solving similar problems? and lastly, Is the mass relevant...
  15. J

    Harmonic motion - Find the Mass held between two Springs

    So first I find the energy using the eqn (1/2)kA^2. Since there are two springs with the same k I multiply it by two to get kA^2. Energy I get is 2.0475, Now I use E=(1/2)m(wA)^2 to find mass. Again since there are two springs I use E=m(wA)^2. m=E/(wA)^2. w=(2(pi))/T btw. I get the answer of...
  16. Mayan Fung

    I Refractive index of a medium in relativistic motion

    I once naively think that the speed of light is also a constant in a medium in all inertial frames which is not the case. I tried to derive the result yet there is a discrepancy from the results I read in some articles. For example, from [Link to unpublished paper redacted by the Mentors], the...
  17. F

    Tension in rope for non-uniform circular motion with air resistance

    I'm trying to solve this problem using an rtz coordinate system, and Newtons second law. I know that mar = (m(v)2)/r. I'm failing to understand how mg and the drag force affects the solution and how I would set it up. I know if it was at the bottom of the circle that mg would be added to the...
  18. E

    Why Does a Sphere Reach Terminal Velocity if Buoyant Force Exceeds Weight?

    in my head this is just a silly problem in which i need to determine the ↓ force (weight) and the ↑force (archimedes bouyant force) and then the difference must be the drag force ↑ (the force that involves velocity) but i can't get any sense out of this answer how is possible for the sphere to...
  19. Purpleshinyrock

    Help me solve this equation please -- Roller Coaster Motion

    Hello. Can someone tell me what area of phisics should I study to better understand this exercise( I ve been looking at kinematics since it asks for the velocity but I can't seem to find where it talks about different points like this) and also what should I do to solve this exercise please? A...
  20. Pipsqueakalchemist

    Engineering Using Cartesian vs. Normal/Tangential Coordinates for Centripetal Motion

    So for this problem the solution used Cartesian coordinates but I was wondering wouldn’t it be easier to use Normal and tangential coordinate because the bar is undergoing centripetal motion? Also on the right diagram shouldn’t the acceleration be down and not up. The reason I think that is...
  21. Pipsqueakalchemist

    Engineering Questions on Forces & Friction: Analyzing Plate & Block Motion

    So I have questions on two separate questions. The first question is about the fbd of the plate attached to the pin. How can there be an Ax since there’s no other force in the horizontal direction wouldn’t the plate start moving on the x-direction due to imbalanced forces. Second question about...
  22. V

    Forces on particle in complex motion relative to ground observer

    A table with smooth horizontal surface is fixed in a cabin that rotates with a uniform angular velocity ω in a circular path of radius R. A smooth horizontal groove AB of length L(<<R) is made on the surface of the table. The groove makes an angle θ with the radius OA of the circle in which the...
  23. P

    Does Raising My Arm Change the Center of Mass?

    Let me imagine myself standing on the Earth with my arm in the resting position perpendicular to the ground. Now if I decide to raise my right arm by 90 degrees, now that it is parallel to the ground. I have shifted my center of mass in this process. But the center of mass will not accelerate...
  24. S

    Motion of box on inclined plane connected by spring to a wall

    a) When the system is in motion for the first time, the force causing ##M## to move is contact force with ##m## so: $$\Sigma F=M.a$$ $$N \sin \alpha=M.a$$ $$mg \cos \alpha \sin \alpha =M.a$$ $$a=\frac{mg \cos \alpha \sin \alpha}{M}$$ Is that correct? b) Is acceleration of ##m## the same as...
  25. H

    Motion of a particle in a magnetic field

    Hi, I have to find the motion of a particles ##(x,y,z)##. However, I'm not sure where to begin. Is it correct to split the problem and first find what's the motion in the x direction then y and z. For exemple, ##m \frac{d^2x}{dt^2} = -kv_{0x} + qv_{0x}B sin 90 ## ##m\int\int...
  26. rg0ldberg

    Projectile Motion with a backwards Rotation/Tumble

    I'm having a bit of a problem with some projectile motion. The standard motion is not a problem, but how to I compensate for a projectile that is rotating or tumbling backwards (nose over tail) at a significant rate of speed. The Tumble rotation is about 50 degrees/second on a cylindrical...
  27. warhammer

    Motion involving Translation & Rotation |Kleppner and Kolenkow

    My doubt is with Method 2 of the given example in KK. I'm unable to understand why the torque around A (where we have chosen a coordinate system at A) becomes zero due to the R x F in z direction with a minus sign {Photo Attached} I have tried to reason out that one way to formulate that term...
  28. P

    Getting the equations of motion for this SHM problem

    Summary:: I have come across a situation where I seem to get different equations of motion for an oscillating system. Please do help me find out where I went wrong. *I am not asking how to solve the problem* I am going to consider 4 parts of the cylinder's motion, as listed below. (There is...
  29. M

    Equations of motion of a 2-DoF Free damped vibration system

    Summary:: What are the Equations of motion for a free damped 2-Dof systrem? Hello, I am required to calculate the equations of motion for a 2-dof system as shown in the attached file. The system is undergoing free damped vibrations. I have found the equations of motion for no damping but i...
  30. abdsaber000

    Periodic vs. oscillatory motion

    I'm hesitated between the first and second choice
  31. A

    I Electric Field seen by an observer in motion

    In Robert Wald's General Relativity textbook page 64 reads: __________________________ In prerelativity physics, the electric field ##\vec{E}## and magnetic field ##\vec{B}## each are spatial vectors. In special relativity these fields are combined into a single spacetime tensor field ##F_{ab}##...
  32. G

    Did I Miss Something in Disputing a Popular Book's Solution on Relative Motion?

    I do not agree, this is bullocks. We can simply set up position vector of ##\vec A(t)## and ##\vec B(t)## with respect to the fixed center of the carousel, their relative velocity is simply ##\frac{d (A-B)}{dt}## or ##\frac{d (B-A)}{dt}## Since this is a pretty popular book, I am wondering if I...
  33. hquang001

    Rotational motion and angular momentum

    mball = 2 kg, mputty = 0.05 kg, L = 0.5 m, v = 3m/s a) Moment of inertia : I = (2mball + mputty ). ¼ L^2 = 0.253125 kg.m^2 Linitial = Lfinal => mputty. v. r = I.ω => ω = (4.mputty.v.r) / I = 0.148 rad/s b) K initial = 1/2 m v^2 = 0.225 J K final = 1/2 Iω^2 = 2.85.10^(-3) J => Kfinal /...
  34. momoneedsphysicshelp

    Simple Harmonic Motion of a Mass Hanging from a Vertical Spring

    Assuming zero spring mass and zero friction, At the greatest value of x, the loss in gravitational potential energy should equal the loss in elastic potential energy. so I did (1/2)kx^2=mgx to isolate x in the formula, x=(2mg)/k then I plugged in my values so: (2*13.6*9.81)/8.8= 30.3218...
  35. RoboRaptor

    A Car on a Banked Curve Moving in Uniform Circular Motion

    First I figured out the normal force being exerted on the car using the equation above. Cos(40°)*(1050*9.8) = 7883N Next, I tried to find out the horizontal component of the normal force by doing: Cos(50) * 7883 = 5067N I figured out the angle by using certain geometrical properties. Next, I...
  36. A

    I Is Heart Rate Invariant in Different States of Motion?

    just something i think about, maybe it difficult to answer. i know, from study, that any observer moving along his world-line - in any state of motion - will not himself notice any difference to the rate which time passes for him. example: his heart-rate will feel normal (well, so long as he...
  37. John Mohr

    Constant Circular Motion Not Really Constant

    I was pondering my practice of talking about circular motion in the horizontal direction and the vertical direction. But I'd often would see in books, notes, and the internet that we assume constant velocity for the vertical case. However, when one thinks about the forces at different points in...
  38. hquang001

    Calculating Distance and Time for One-Dimensional Motion in Physics

    total time: t = 36 mins = 0.6h = t1 + t2 => t2 = t - t1 = 0.6h - 0.1h = 0.5h Vmax = a1 x t1 Vat C = Vmax + a2t2 substitute Vmax in Vat C we have : 0 = a1 x 0.1h + (-600 km/h²) x 0.5h => a1 = 3000km/h² Vmax = a1 x t1 = 3000 x 0.1 = 300km/h I check the result by: x1 = ½ a1 t1² = ½ . (3000)...
  39. Ibby321

    Vertical motion through an electric field

    I know that the answer is 0 J (no NET work was done) because there is symmetry to the problem and this symmetry comes from the fact that the direction of force changes, BUT I don’t know why the force changes (I have an idea; TBD below in #4). When I did this problem I thought I could find the...
  40. R

    Projectile Motion -- Help please understanding these basic problems

    1)Find the range of the gun when the muzzle speed is 400m/s and the elevation 24.5° - I tried to find " Time " via t= [v-u]/a by substituting it through cos--> t= ( 0- [400cos24.5] )/-10 and got [ 36.39 ]. Which I then substituted in S=ut---> S= ( 400cos24.5 ) x 36.39=13245.3. [ the answer...
  41. L

    Circular Motion Questions (energies, forces, angular velocities, etc.)

    Question 1: I believe that the ratio would be b. 8:1 because by combining the formula for kinetic energy and momentum the expression Ek=p^2/2m can be obtained. Thus, for a body of mass 2kg with twice the momentum: Ek=2^2/2*2=1 For a body of mass 4kg with half the momentum: Ek=1^2/2*4=1/8...
  42. T

    Change in the direction of motion of the particle

    Unfortunately, I have no idea about a possible solution.
  43. J

    Equation of motion of a chain with moving support

    In the figure assume the "ceiling" moves with motion ##Y(t)##, i.e. it is a point support. Applying Newton's law in the vertical direction ##T(y).\hat{y}=\rho y[g+\frac{d^{2}Y}{dt^{2}}]## If ##\theta## is the angle between ##T## and ##\hat{y}## that means ##|T|\cos\theta=\rho...
  44. V

    Why Does Friction Provide Centripetal Acceleration in Circular Motion?

    Suppose a particle is moving around a circular track of radius R at speed v. To bend around a circle some agency has to exert an acceleration towards the center of the circle. I analyze the forces acting on the particle, its weight and the normal force and there is no acceleration in the...
  45. Matejxx1

    Describe the motion of yoyos suspended from the ceiling

    I have trouble solving this problem any help would be appreciated.Problem statement ##J=\frac{mr^2}{2}## a) Determine the motion of yoyos for ##n=1,2,3## The case for ##n=1## is simple, however, I am having trouble with ##n=2## and ##n=3##. for ##n=2## I started by drawing all the forces...
  46. E

    Classical The motion of cats and stuff in free fall

    Hey everyone, where can I learn fairly rigorousoly about continuum mechanics and specifically about how to map between motions in the configuration space ##\mathcal{C}## and motions in the shape space ##\mathcal{C} / SO(3)##? I would like to model the general motion of deformable bodies with...
  47. sergiokapone

    I What does motion mean in quantum mechanics?

    Consider the Schrödinger equation for a free particle: \begin{equation} -\frac{\hbar^2}{2m} \partial_i^2\psi = i\hbar\partial_t \psi. \end{equation} Let us be interested in the motion of a free particle in quantum mechanics. We say ok, we have a solution to the Schrödinger equation for a...
Back
Top