The description of the movement of bodies by their position, velocity, acceleration (and possibly higher time derivatives, such as, jerk) without concern for the underlying dynamics/forces/causes.

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Branching ratio for a bound state

Consider the meson $\Upsilon(10860)$. It decays into $B\bar{B}$, $B\bar{B}^*+cc$ and $B^*\bar{B}^*$. The mass of $B$ is $5.28 ~\textrm{ GeV}$ and mass of $B^*$ is $5.33~\textrm{ GeV}$. The branching ...
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166 views

Free-Fall Lab Help - Getting weird results

So, I am doing a free-fall lab for my physics class. We got the values and I have the results here(we used a infrared photo-gate). Basically, we have a brass cylinder and a wood cylinder. Each are ...
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294 views

Modelling an Inelastic Collision

I've attempted to model the inelastic collision between a moving mass and a large stationary object, e.g. dropping an ball on the floor, for analysing the approximate kinematics and heat dissipation ...
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30 views

Motion decomposition (Relativistic case)

When an electron moves at very close at $c$ (speed of light), is it physical to decompose the motion in two other directions (like what we do in classical case). If so, the motion in each direction ...
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99 views

Heads, Tails… Edge?

No Nobel prizes at stake, but just an idle thought and an idle question. How could one calculate the probability of a flipped coin landing stable on its edge, instead of heads or tails? I assume ...
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251 views

What does kinetic energy at infinity mean in terms of supernovae?

I have noticed that in some paper that the term "kinetic energy at infinity" is used. I understand what potential energy with reference to infinity mean, but what does the term kinetic energy of ...
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303 views

Air resistance of a general shape object

I'm trying to code a simple physics simulator in C++ but I'm stuck on the air resistance issue. Surfing the Internet I only find a drag coefficient for very basical area shapes when the air is ...
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321 views

How to model an accelerometer measurements on a car wheel?

I am working on kinematically modelling an accelerometer on a car wheel. When working on the initial conditions, I am confused whether or not I should use the gravitational acceleration since there ...
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664 views

How do I find equations for the distance of the planets relative to one another?

I know I should be able to piece together some basic Newtonian equations for this, but I'm not sure where to start. I want to be able to choose one planet as the center and calculate its distance ...
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38 views

When this CD is spun so fast that it shatters, why does the warped shape move slower than the surface?

In this video where a CD is spun abnormally fast to the point of shattering, one notices from the writing on the CD that the surface is spinning faster than the warp "shape" is. In other words, the ...
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23 views

Decay kinematics of Higgs boson

So I'm looking at a two-body decay question for the $h\rightarrow\gamma\gamma$ decay channel for the Higgs Boson. I am asked to find the invariant mass of the Higgs boson. I'm not too sure how to ...
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62 views

How do I model the motion of a particle changing acceleration vector (2D)?

I want to model a particle with an arbitrary initial velocity, and estimate the time it takes to reach a final point given a constant magnitude of acceleration. It should take the quickest path to the ...
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85 views

Inverted pendulum with reaction wheel

I'm a little confused about the equations of motion of the reaction wheel pendulum. It is used in self balancing bicycles - see vide link in comments (I can't add another link here due to low rep). Or ...
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21 views

Kinetic energy vs Kinetic Energy scenario in a collision, mechanical energy used for work?

Most collisions have Kinetic energy conserved or in the case of inelastic collisions energy is lost into other forms. Though the equation of "TMEi + Wnc =TMEf" is true however, what if two unequal ...
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62 views

How could a heavy manhole cover jump out of the ground, fly through the windshield and hit a driver in a car?

Today (12 of Feb), there was this accident in Boston where a driver was killed because a manhole cover (~200lbs) had somehow become airborne and struck her. The car looks like an SUV, so her head must ...
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41 views

3 Particle problem with a difference

Please read this completely, it is not the typical question you expect. 3 particles are at the corners of an equilateral triangle with side a. Assume that particle 1 is at (0,0), particle 2 is at (a,...
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39 views

Calculation max speed for a particular speed profile, distance and time?

For work I have to calculate the maximum speed for a machine. The machine has a certain speed profile which must be followed. Besides this this speedprofile has to be followed within a certain time (...
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54 views

Needed acceleration input to reach a target point

I have a point mass traveling on a 2D plane with some initial velocity v and initial position r. The point mass is able to ...
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60 views

Elastic Plastic with Kinematic Hardening Material Model

I have a model which calculates the rate of deformation tensor using the Green-Lagrange strain rate, the material velocity gradient and the gradient of deformation tensor. $$\bar{\bar{D}} = \bar{\...
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37 views

irreversibility Aristoteles law of motion

I am watching the second lecture from the theoretical minimum and do not understand the argumentation of Susskind. For those who do not want to watch the video. It is about the law of motion from ...
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105 views

Dynamics and kinematics of quantum field theory

What is the difference between dynamics and kinematics of quantum field theory? I read that in QFT there is no possibility to keep the two things distinct because of a problem with the separability of ...
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61 views

Total cross section of particle decay

Suppose a particle A travelling along the $z$-axis and decays into particles B and C. The cross section is given by $$\frac{d\sigma}{d\cos\theta^*} = k(1+\cos\theta^*)^2$$ where $k$ is a constant ...
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77 views

How Burmester's theory converts rotary motion of the crank to linear movement?

I have been studying the mechanism of Klann's Mechanical spider and there it was written that by Burmester's theory it converts rotary motion of the crank to linear movement. I tried searching but how ...
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86 views

Is shaking a phone enough energy to charge a smartphone?

Is shaking a phone enough energy to charge a smartphone? For example I'd like to use some kind of power generator to charge smartphone's battery but I'm wondering if shaking (by hand, or motion when ...
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41 views

Web utility for viewing $x$-$t$, $v$-$t$, and $a$-$t$ graphs

I'm wondering if there exists any utility on the web which displays $x$-$t$, $v$-$t$, and $a$-$t$ graphs for, say, a number of well considered example animations. The utility should allow pausing, ...
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41 views

Why we don't integrate intital velocity in body cast equation?

On this site I've found a formula for calculating the $x, y$ coordinates for a body throwed by an angle to a horizon. It looks like this: $$x(t) = V_0 t \cos(\alpha); $$ $$y(t) = V_0 t \...
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78 views

How makes an equation to Flipping motion

Every now and then, I find myself reading papers/text talking about how this equation is a constraint but that equation is an equation of flipping which satisfies this constraint. Indeed, This ...
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115 views

Force needed to change momentum, from fixed position

I have a situation where I want to change the velocity of a mass, by applying a force from a fixed position. For example in the diagram below, the mass starts with the initial velocity in the upper ...
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293 views

Getting pairs of angle and velocity for a projectile to a given destination

I'm trying to calculate the initial velocity $v_0$ and angle $\theta$ for a given destination $(x, y)$ with a launch height of $y_0$. Obviously there will be a set of pairs of velocity and angle that ...
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74 views

How to calculate the correct coordinates from a distorted video of a projectile?

I am working on a high school project that is related to projectile motion. I am exploring how exactly the position of the center of mass affects the trajectory of a long but thin, javelin-like ...
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103 views

Kinematics algebra, pT, Peskin Eq.17.59

my question concerns the kinematics of 2 to 2 particle scattering. I refer to Peskin and Schroeder eq.17.59 going from this expression $\frac{d^3\sigma}{dy_3dy_4dp_T}=x_1f_1(x_1)x_2f_2(x_2)\;2p_T\...
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274 views

How to calculate the resulting velocitys and rotation speed after two concave polygons collide in 2d

so I've been searching google for how to do this, but all anyone seems to care about is collision detection =p, and no results come close to teaching me how to calculate 2d elastic collision between ...
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305 views

Kinematics textbook illustration

I have trouble interpreting this illustration. I see why r (position) and a (acceleration) are the way they are, but what happened to v? Why is it smaller than its coordinates? Is this another error ...
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25 views

Kinematic problem (initial acceleration)

A ball is rolling over a soccer field with constant velocity $V_{b} > 0$ at an angle of 45┬░ to the goal line. It starts at the corner of the field (distance $d$ from the middle of the goal line) at ...
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31 views

Does this calculation give displacement or distance?

So we have velocity as a function of time given $\overrightarrow{v}(t)=(1-2bt)k\overrightarrow{r_0}$ where $b,k$ are positive constants and $\overrightarrow{r_0}$ is a unit vector. It is found that if ...
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57 views

Physical pendulum dynamics confusion

I'm validating a Matlab Simulink SimMechanics model analytically. The model consists of a physical pendulum (uniform rod with length $l$ and width $w$) which is torque driven. I'm somewhat confused ...
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22 views

kinematic constraint of spacecraft

I am now reading a paper about trying to use convex optimization to solve the attitude control of spacecraft. However, I do not have background on the physical part: Let 1. $\omega(t) = [\omega_1(...
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20 views

Particle interaction kinematics in lab frame

Attempting a question from a past paper on scattering kinematics, fixed particle mass $m$ is struck by another particle mass $m$ with kinetic energy $T$. By evaluating $s$, $t$ and $u$, and their sum ...
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17 views

Kinetic gas theory: How large are rotational and vibrational energy for a linear diatomic molecule?

Let's say one has given a temperature of a simple linear diatomic gas like Hydrogen $H_2$. From the temperature one knows the energy of the gas, but how does this energy "split up" to the different ...
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21 views

Magnitude of Drag force correction on a bean bag

I am currently designing a ballistic launcher for an engineering project. Our task is to propel a bean bag approximately one hundred grams in mass ten feet with the lowest standard deviation possible. ...
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33 views

Helicity of massive particle at high enengy

We know that massless spin-1 particle like photon only has two helicity state (-1,1), what about the helicity of massive spin-1 particle (W boson) at very high energy? Does it have helicity 0 state ...
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51 views

What kind of unit is $m^2s^{-4}$ in terms of gyro/accel?

Background While working on something in the field of avionics, I have discovered the following unit as part of an inertial-physics equation... $$m^2s^{-4}$$ I am trying to figure out the formal ...
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36 views

graphical representation of Maxwell velocity distribution law

I have read Maxwell's distribution law it is the probabilistic representation of no. Of particles having velocity between $c$ to $c+DC$,through this representatation we can get the number of particle ...
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32 views

Relation between linear and rotational motion of molecules?

The temperature of a substance, such as an ideal gas, can be related to the root mean square speed of the molecules. For example, for gases the molecules travel at about 480 meters per second. If we ...
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47 views

About the formula of pendulum simple

for the modulation and the simulation of a pendulum simple , I'm Find this formula : a(t) = a0 * sin ( sqrt(g/l) * t * Pi/2 ) - [ k/(mll) * cos ( sqrt(g/l) * t * Pi/2 ) * t ) ] ...
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45 views

Velocity of an object rolling down a spiral

Imagine a fiction less spring-like spiral, an object will roll down the wire path the spring creates. From conservation of energy, the initial PE will be equivalent to gravitational potential energy, ...
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32 views

What is the derivative of the length vector in the direction of the original unit vector?

What is the derivative of the length vector? I am asking this question becuase I have seen, in Prof. M. S. Sivakumar's youtube video, the result that $\dot{|r|} \hat{r} = \dot{r}$ Where, $ \mathbf{r}...
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36 views

Why does a curved spacetime result in a movement?

If gravity is not a force but a curvature of spacetime, where does the motion towards the center of gravity come from? To put it differently, why would two objects in a space fall towards each other ...
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51 views

Finding the distance a spaceship would travel given a time of departure and velocity

Let's say a spaceship leaves Earth at a day t and with velocity v. Is there a way to know how many kilometers it will cover to arrive on Mars? This would be a trivial question were it not by the fact ...
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19 views

Calculating the distance of a piston from the crank center

I stumbled upon this [https://en.wikipedia.org/wiki/Piston_motion_equations#/media/File:Piston_motion_geometry.png ] and was wondering, if you can determine the position of the piston (x) by the law ...