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

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0answers
13 views

Kinematics-Motion in one Dimension [on hold]

A man is standing on top of a building 100m high. He throws 2 balls vertically, one at t=0 and the other after a time interval(less than 2s). The later ball is thrown at a velocity of half the first. ...
0
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2answers
26 views

Horizontal and vertical acceleration of a ball on a slope?

I understand that you resolve the components of the balls weight parallel and perpendicular to the slope in order to calculate the force due to gravity that actually acts down the slope. The ...
2
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3answers
81 views

Does acceleration follow the same addition like velocity?

Two frames have relative velocity $u$, but an object in one is initially at rest and in the other has velocity $v$. If it then starts to accelerate, the acceleration measured in both frames is equal. ...
3
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2answers
59 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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1answer
18 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: ...
0
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2answers
47 views

What objects' masses do we need to take into account when calculating force?

In the following problem: A steam engine of mass $3\times 10^4\ \mathrm{kg}$ pulls two wagons each of mass $2\times 10^4\ \mathrm{kg}$ with an acceleration of $0.2\ \mathrm{m/s^2}$. Neglecting ...
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0answers
43 views

If a spaceship accelerates enough can it overcome spaghettification?

If a spaceship accelerates at the right amount would that counteract the spaghettification caused by falling into a black hole?
0
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1answer
70 views

Do black holes have a puff pastry point?

If a person falls into a certain sized black hole they accelerate very fast, which increases the g forces on them. These g forces flatten the person out into a pancake. As the person falls further ...
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2answers
35 views

Save a falling person by nullifying their mass or reversing gravity [closed]

Let's say you have the superpowers to manipulate matter, mass and gravity. Imagine a person falls off a plane, flying few kilometers above the air, and they are about to get splattered onto the hard ...
0
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0answers
16 views

Could diamagnetism be used to create an airbag for your internals?

Could a massively strong magnetic field be used to shield a human body from the effects of excessive +/- accelerations? My understanding is that say for a pilot suitably strapped in that the strain ...
0
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2answers
83 views

Convert an equation for acceleration into one for velocity

A sledge is pushed in a straight line. Assume surface is smooth. When the sledge is x distance away from the start the magnitude of its acceleration is given by $0.08e^{-4x}$ and is going in the same ...
3
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2answers
169 views

General Relativity and acceleration

Suppose I am riding an amusement park ride. This ride is a circular Plexiglass structure that spins at high speed. If I measure the circumference of the structure(while the ride was spinning) with a ...
0
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0answers
35 views

MEMS Accelometer and Gyroscope data fusion for counting cycles

I will simplify my scenario as follows: a 6-DOF MEMS gyroscope and accelerometer unit is placed on the edge of a rotating wheel and the goal is to count the number of cycles using any of the units of ...
1
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2answers
56 views

Which moment of intertia do I need to calculate torque

I'm trying to calculate the torque needed to rotate an array of solar panels. I've found some formulas for calculating torque, but they require moment of inertia. I designed this array in Autodesk ...
0
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1answer
27 views

The equivalence principle and experiments concerning it?

Imagine that we are in a rocket accelerating with some magnitude $a_1 = dx^2/d^2t$, also imagine that we have a stationary rocket ship in close proximity to ours, stationary relative to our reference ...
-3
votes
6answers
110 views

A contradiction statement to $F=ma$ [closed]

If I thrown an object of mass 1 kg up in the air it will always fall with an acceleration of 9.8m/s. If I throw it very high up in the sky, it falls with a greater force as compared to if i throw it ...
3
votes
1answer
26 views

How does a body accelerate that is put into a flow field with constant speed?

Imagine an infinitely long flow channel filled with water flowing at a constant speed everywhere parallel to the infinitely long dimension of this channel. Furthermore, imagine we place a body (say a ...
0
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2answers
48 views

Barrel length, not PSI, determines acceleration?

In 5:49 in this MythBusters video https://www.youtube.com/watch?v=74K3IYOM7Lg, the MythBusters Jamie and Adam believe that barrel length is the deciding factor in acceleration, more so than PSI. Why ...
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2answers
69 views

Does acceleration warp space?

I know that mass warps spacetime and gravity and acceleration are equivalent so does acceleration warp spacetime too?
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1answer
84 views

Why we can't define energy in accelerating frame?

In my old unanswered question about accelerating frame, I have found (later after editing that question), that one of the keys is that energy is not defined in accelerating frame. What I do not ...
0
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1answer
51 views

Current Electricity

If $$ \frac{dQ}{dt} = I $$ and if an accelerated current produces E.M. waves (radiation), does that mean $d^2Q/dt^2$ (second derivative of a charge w.r.t. time) will give me the magnitude of the wave ...
0
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1answer
39 views

Boat Deceleration on Collision [on hold]

I have a question regarding acceleration. When a boat collides with tires and they compress on contact and the boat is slowly brought to a stop, how is deceleration factored into this? As in, what ...
-1
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2answers
50 views

Does light ever experiences acceleration? [duplicate]

Till now I have learned that light has fastest speed. But I have also noticed that wherever it travels it only experiences retardation. So I wanted to know if light ever felt acceleration naturally in ...
2
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3answers
59 views

Einstein's principle of equivalence; Standing on earth vs sitting in accelerated car

When I am seated in a car that is accelerating in a particular direction I could, for example, throw a ball and it would appear to be flying the opposite way. With the windows covered etc. An ...
0
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1answer
25 views

Velocity change of air down a cone?

Does the velocity of fluids(specifically gasses) change when traveling down a cone from the wide opening to the narrow opening? If so, is there an equation used to calculate the acceleration or ...
2
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2answers
51 views

Will the gravitational pull of air affect the falling rate of an object?

After looking at this question: Don't heavier objects actually fall faster because they exert their own gravity? A thought occurred to me that due to the increased gravitational pull of the ...
0
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1answer
30 views

Calculate constant acceleration for a length of track with start at rest and final velocity known [closed]

My maths and physics are rusty... I'm a bit ashamed, but I have this problem: Let's have a 1000m linear accelerator (mass driver) propel a payload at constant acceleration, with a final velocity of ...
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3answers
54 views

Velocity and acceleration with variable friction

If you have a body on a table,with a velocity $u_0$, going from a non friction area to a friction area, how do I find the function for velocity and acceleration due to the variable friction force(T). ...
28
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8answers
7k views

Why does a free-falling body experience no force despite accelerating?

Note: For the purposes of my question, when I refer to free fall assume it takes place in a vacuum. From my (admittedly weak) understanding of the equivalence principle, falling in a gravitational ...
0
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1answer
17 views

How to calculate the “angular braking distance” when you know the following values?

I have to calculate the arc length in radians that a circle spinning at speed will travel when it decelerates to $0$. I have the initial angular velocity in rad/s, the radius in meters, the mass in ...
4
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5answers
449 views

Intuitive answer to a kinematic problem

The problem: Two particles A and B start from rest and move for equal time on a straight line. The particle A has an acceleration a for the first half of the total time and 2a for the second half. ...
0
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2answers
29 views

Engine fuel consumption vs power

Something that has bother me for a long time is why a 600 hp engine uses more fuel per kilometer than a 80 hp engine. Let pretend I have two equal cars (same shape same weight etc) except for the ...
0
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2answers
56 views

Calculating acceleration of a car going downhill [closed]

Let's say a car is driving down a hill. Throughout the descent, you have access to the car's speedometer, a stop watch, and GPS altitude readings. You also know the car's mass if that helps. How would ...
3
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1answer
57 views

What force decays an oscillating charge?

Consider this scenario: We have a charge on a spring. As it oscillates, it loses energy to radiation. What force decays the oscillation? As far as I can see, the only forces in the scenario are ...
1
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1answer
44 views

Condition for 2 bodies to move together

The condition for 2 (or more) bodies to move such that they are always in contact, is that their accelerations (and velocities) along their common normal should be same. Can someone explain why this ...
0
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0answers
37 views

Gravitomagnetic railgun

Would a gravitomagnetic analogue of a railgun work as expected, in theory? Consider replacing the electric currents on each rail with mass currents. Then place a mass between the rails, moving with ...
0
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3answers
110 views

A simple derivation of the Centripetal Acceleration Formula?

Could someone show me a simple and intuitive derivation of the Centripetal Acceleration Formula $a=v^2/r$, preferably one that does not involve calculus or advanced trigonometry?
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0answers
30 views

Radius of apparent event horizon for accelerating observer

This question is related to my last question on the Unruh effect, which can be found here. First, recall the quote from the Wikipedia article on the Unruh effect: An accelerating observer will ...
2
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1answer
71 views

Unruh effect and relative acceleration

This is how I understand the Unruh effect: if a person (say, Bob) is moving with acceleration $a$ in his spaceship, then he will see an apparent event horizon around him--that is, the vacuum will ...
2
votes
2answers
108 views

Twin paradox caused by gravitational difference in space

I am not a physicist, but have always been curious about the twin paradox. So, here is my question. There are two twins in space - Twin A and Twin B (both stationary). They are apart from each other ...
2
votes
7answers
552 views

Free fall into circular motion

If I'm on a roller coaster free falling from height $h$ and then suddenly start going into horizontal motion with a radius $r$ of turn what is the $g$-force I experience? I worked out the equation ...
1
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1answer
70 views

Is gravity's acceleration rate - squares of all natural numbers? [duplicate]

I've seen some science\history documentary in which they made a replica of Galileo's inclined plane experiment. They rolled a ball down the plane; and it's progressed in length units each unit of ...
1
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3answers
74 views

Calculate acceleration from power [closed]

I am currently programming a simple computer space ship simulation. This is just for fun to train my programming, 3D graphics and a little bit of physics skills. What I want is the user to pick a ...
0
votes
1answer
39 views

How to know if a body is travelling with uniform acceleration or not?

One of the Example in my Textbook is A body travels a distance of 2 m in 2 seconds and 2.2 m in next 4 seconds. What will be the velocity of the body at the end of 7th second from the start. In ...
1
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1answer
52 views

Gravitational “acceleration” and frequency change of a photon?

For massive particles, force translates into acceleration which again is a change of the velocity vector in direction and/or magnitude. For a photon, the velocity magnitude cannot change, only the ...
0
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1answer
46 views

Calculating time and speed change on downhill incline

I am trying to calculate the time and final speed if lets say a bike with constant speed of 20km/h of goes in this incline (downhill), what would be its speed after say $M$ meter ? I remember the ...
0
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0answers
23 views

Shaft acceleration with a gearbox

I'm trying to calculate the shaft acceleration when there is an engine, a gearbox, and a load. I've seen the equations which change the reflected inertia via the gear ratio, relate the speeds and ...
0
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0answers
46 views

Deduce v(t) from power and torque

I'd like to know if this is possible to draw the highest curve of $f : t \longmapsto v(t)$ of an accelerating car based on power and torque curves like this one (EV) or this one (TV). I assume we ...
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1answer
51 views

Proof of (Vi + Vf)/2

Its quite intuitive that when you have constant acceleration, the average velocity is given by (Vi + Vf)/2, but how can you prove it?
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1answer
33 views

If velocity for an interval is zero then is acceleration also zero throughout?

We know that if velocity is zero for an instant, then acceleration need not be zero (a simple example of which is a ball thrown upwards.) But if velocity is zero for an interval, will ...