Questions tagged [acceleration]

The rate of change of velocity of a body per unit of time.

201 questions with no upvoted or accepted answers
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14
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2answers
353 views

Can the question of a gravitationally accelerated charge radiation be tested experimentally?

I know that the question of radiation from a gravitationally accelerated charge has been discussed extensively at Does a charged particle accelerating in a gravitational field radiate?. Yet the ...
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3answers
761 views

Is acceleration continuous?

The extrapolation of this Phys.SE post. It's obvious to me that velocity can't be discontinuous, as nothing can have infinite acceleration. And it seems pretty likely that acceleration can't be ...
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1answer
118 views

Parametric and covariant expressions for the acceleration vector

I am reading S. Neil Rasband book about Classical Dynamics. In the first chapter, there are two different forms of the acceleration: What he calls the "intrinsic". Given a trajectory with parameter $...
4
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1answer
343 views

How to measure gravitational acceleration in airplane?

I want to see (actually: show to my kids) evidence of the $1/r^2$-decay of gravitational acceleration by measurement, in a way as simple as possible. So I was thinking of measuring gravitational ...
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66 views

Understanding the tidal force tensor

I'm just looking to gain a basic intuitive understanding of the forces at work in tidal stripping and their direction/motivation etc. I'm struggling to grasp the underlying principles and it is making ...
3
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0answers
78 views

What is the acceleration of expansion?

If me and my pet duck, who weighs next to nothing, were placed far away from any gravity source and in such a way that our mutual attraction was negligible, would I see my duck accelerate away from me?...
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140 views

Law of motion of accelaration applying average velocity

Consider the law of motion of acceleration: $s=1/2at^2$ Develop the law decomposing the acceleration: $s=1/2 * (V/t) *t^2 = 1/2*(V*t) = V/2 *t$ So we can say that the space is the moltiplication ...
3
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145 views

Acceleration vector of tipping object (robot)

I am about to develop a simulation application of a robot. For that reason, I would need to calculate the acceleration of the robot (centre of mass) when its centre of mass exceeds its feet (ie it ...
3
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1answer
156 views

When is a circle not a circle?

Imagine a 2D uniform circular motion of constant magnitude but changing direction in an area of zero g. The forces will be equal all the way round - it will be a perfect circle. Now imagine the same ...
3
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2answers
97 views

Shape and even connectedness of accelerating components in SR is frame dependent?

In some inertial frame consider a disk of radius 1 lightyear at rest. Then along the edge of the disk there are some people in spacesuits at rest hovering right above the disk (which has negligible ...
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0answers
290 views

How do we derive force/acceleration vectors from Einstein's field equations?

I'm new here and I don't have any formal experience in physics beyond A-level. I've been exploring an idea for a space sim game someone else is developing in which propulsion of a spacecraft is ...
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77 views

Does tilting a liquid develop shear stress on its surfaces?

Please help me these confusions I have. If I tilt a cuboidal container containing an ideal fluid (non viscous liquid), does a shear stress develop on the liquid due to some shearing force acting ...
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How did Henry Kater measure distances down one part in $10^5$?

Wikipedia says that in 1817, Henry Kater was able to measure distances accurately enough to get at least five significant figures in a measurement of $g,$ suggesting that he could measure a distances ...
2
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48 views

Acceleration interpretation in accelerated frames in general relativity

I would like to know whether my physical interpretation of some dynamics in accelerated frames is correct. In a frame with acceleration $a$ we have the metric $$ds^2 = (1+ax)^2 dt^2 - dx^2$$ The ...
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156 views

Newton's Principle of Determinacy (intuitive explanation)

I was reading Arnold's Mathematical Methods of Classical Mechanics. In it he speaks of "Newton's Principle of Determinacy". He says for a mechanical system (collection of point masses in 3D Euclidean ...
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2answers
167 views

Does accelerating magnet emit radiation?

Just like accelerating charge produces emits radiation, does an accelerating magnet emit electromagnetic radiation?
2
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1answer
105 views

In special relativity, is there a prescription to find the coordinate transformation to a general (for instance accelerated) observer? And in GR?

Suppose we are in an inertial frame, so that the metric in our coordinates is just the Minkowski metric, \begin{align} \text{d}s^2 = -\text{d}t^2 + \text{d}x^2 + \text{d}y^2 + \text{d}z^2. \end{align} ...
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1answer
1k views

Relative acceleration of bodies on opposite sides of a pulley

This is a problem that I encountered while solving problems related to constrained motion: With all the data given in the above question, I believe that the monkey just holds on to the rope and does ...
2
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0answers
82 views

How can I calculate a brachistochrone-like transfer burn with a changing acceleration?

I'm working on a sci-fi story with a few locations set across the solar system, and I want to make sure that it works as accurately as possible. In order to hop from planet to planet, the ships use ...
2
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0answers
758 views

How to calculate acceleration vector of a moving object to intercept a stationary object

The short version: I'm moving on a certain straight-line trajectory (two dimensions only, thank goodness), and I want to intercept a stationary object, with constraints on maximum acceleration and ...
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3answers
719 views

How to draw a velocity curve from Engine power, weight and traction?

Not sure if this is the right forum but I would like to plot a velocity curve of a train, starting at 0km/h and accelerating up to a max speed. The data I have for the locomotive engines are: ...
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4answers
806 views

What is the effect of torque steering on a motorcycle with a long wheel base?

From experience, it appears motorcycles with a large wheelbase coupled with a long handlebar (say a modified Harley Ape Hangar) shows a noticeable tendency to veer to a side during acceleration vs a ...
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335 views

Odd experiment results (electromagnetics)

Okay, a bit of background. So I'm working on a linear accelerator (you might know it as a Gauss rifle), and I had worked through the equations I thought I needed (Magnetic force, displacement, etc.) ...
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366 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 ...
2
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2answers
59 views

Universe expansion from initial explosion

If the universe is expanding at an accelerated rate, is it because it hasn't reached its maximum velocity from initially exploding? I'm thinking in terms of a bullet being fired from a weapon. It ...
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1answer
3k views

Electrons and Magnetism

Electron at rest generates Electric field. Electron moving without acceleration produces electric and magnetic field. Electron moving with acceleration produces electromagnetic waves. Please explain ...
2
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1answer
119 views

Are there bounds or measurements on the derivative of acceleration (jerk)

The title says it all. Is there a physical maximum value to the 3rd derivative of position? Common Lore says that there is not and that jerk does not play any role in physics. My guess is that there ...
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1answer
18 views

Cylinder rolling down an incline in a vacuum

Say you set up an experiment with an inclined plane, and a cylinder rolling down the plane. Let's also let the experiment happen in a vacuum, such that there is no air friction. However, let there be ...
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0answers
20 views

Acceleration statistics at thermal equilibrium for a simple atomic system

Consider a case of a simple liquid, say argon or Lennard--Jones potential. What are the statistical properties of acceleration at equilibrium? For example, acceleration distribution or a correlation ...
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2answers
106 views

Acceleration in general relativity

Let's say that, from my point of view, another observer is accelerating. Now, from his point of view, he is standing still: all he feels is an overall fictitious force of gravity, which is just a ...
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0answers
28 views

How would one calculate velocity with respect to time in Case 2?

Case 1. : The rocket is weightless in space. It's fueled with propellant. It's wet mass is starting mass $m_s$ and dry mass final mass $m_f$. Suppose rocket's initial velociti is 0. The rocket ignites ...
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1answer
36 views

Calculating acceleration of an object using $x$, $y$ and $z$ coordinates

I have x, y and z coordinates for a test I had carried out for a tool. I had an accelerometer installed on the tool and I used two types of motion to move the tool, rotation and translation. Right now ...
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1answer
86 views

Length contraction of an accelerating rod

Let us assume a rod of length, $4l$, initially at rest. The coordinates are defined s.t - (assuming uniform density) $$X_{back-end}(0) = -2l$$ $$X_{front-end}(0) = +2l$$ $$X_{mid-point}(0) = 0$$ ...
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61 views

When will a person falling into a black hole be crashed by tidal forces?

Assume that a person can resist $30g\approx 300\frac m{s^2}$ (remark: the record is actually at 46.2). I want to solve for the distance $r$ at which a $1.5m$ tall slim person falling radially into a ...
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0answers
54 views

Does the proper four-acceleration $A^{\mu} = (0,0)?$

Let the proper four-position vector $x^{\mu}(\tau) = (0, \tau)$. Differentiating this successively wrt $\tau$ I get the four-velocity $u^{\mu}(\tau) = (0, 1)$ and then the four-acceleration $A^{\mu}(\...
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1answer
126 views

Are Maxwell's equations valid in a rotating frame?

Maxwell's equations are covariant under Lorentz transformations. Are they covariant under going to a rotating frame and if not how do they look?
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2answers
40 views

Can anyone explain me how do I calculate torque?

For my gate automation project, I estimated the amount of force required (in order to estimate the torque) to pull my gate with a spring balance. The display on the spring balance read $2 \text{ kg}$. ...
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1answer
143 views

Energy consumption from acceleration

I have an interesting problem. I have a machine which has to lift 35 kg (this is the total mass of the object and the lifting arm). The lifting is done by a servo motor. Now I want to calculate the ...
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0answers
39 views

Acceleration from scalar-matter coupling in classical field theory

I have came across a text where an interaction term in a classical Lagrangian is presented that couples a matter density $\rho$ and a scalar field $\phi$ as \begin{equation} \mathcal{L}_{\text{int}} =...
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0answers
64 views

The flyby anomaly, rotation, and gyroscopes: help understanding the theoretical connection

The flyby effect in spaceflight is described in the question Is the Flyby Anomaly still a thing? It is an very small unexplained acceleration seen in some spacecraft trajectories during flyby ...
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4answers
88 views

Force of impact the same regardless of which object is moving?

My friend is trying to tell me the force of an impact of riding a bicycle into a stationary car at a speed $v$ will be the same force as if the car is traveling at the same speed $v$ and drives into a ...
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0answers
29 views

Calculating an acceleration from 3 axis MEMS

I installed a MEMD sensor on a motor that I can control the motor speed. I'm recording the information from the sensor (x, y, z) I'm trying to compare if the MEMS sensor reading is ad the same as my ...
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0answers
123 views

Relative acceleration

If the accelerations of two objects are such their one of their components are directed opposite to each other , while the other components are directed in the same direction , then why is relative ...
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0answers
138 views

Infinite current carrying wire, moving parallel to it's current flow direction?

At $t=0$ current flows in an infinite wire, and creates a magnetic field, after sometime the infinite wire begins to accelerate(only the wire wile $I$ remains constant), in a direction parallel to the ...
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Determining the mass of my car via m = F/a

I'd like to do something unconventional. I'd like to weigh my car by hitting the gas. I have an accelerometer in my phone (a). I'm trying to determine the force the car is exerting (against the road, ...
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0answers
27 views

Avoiding inertial affects by accelerating larger mass in 2 body system

Suppose two bodies S and L are in proximity (asteroids say). L is substantially larger than S. For simplicity, let them initially have negligible angular and linear velocity. S will begin to fall ...
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1answer
85 views

Gravitation Acceleration in General of Kerr-Newman Black Hole

The surface gravity (acceleration at event horizon, as measured by an observer at infinity, since the proper acceleration is infinite) of a Kerr-Newman black hole is given (e.g. here) as:$$ \kappa ...
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3answers
150 views

Misconception regarding Wedge constraints motion

The block of mass $m$ slides on a wedge of mass $m$ which is free to move on the horizontal ground. Find the acceleration of wedge and block. Sol. Let $a$ acc. of wedge and $b$ acc. of block w.r.t. ...
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0answers
260 views

Can I calculate the downhill force with the data of a smartphone sensor?

Apologizes for the long explanation, I couldn't find a shorter one. I'm working on a project and want to calculate the downhill force only with data I can get with the sensors of a smartphone. I ...
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1answer
44 views

Measurement location on a rigid body

I am just wondering if it is possible to calculate/estimate the location of measurement point on a rigid body? For example, lets say we have a rigid body that is in motion. We attach a sensor, say an ...