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

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1answer
25 views

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

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 ...
-1
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3answers
47 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). ...
26
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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 ...
-5
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0answers
20 views

Find tf and end distance [on hold]

Mass = 30kg, Velocity = 30, Acceleration = unknown, end distance = unknown, force = -20N. Please breakdown formula in elementary physics terms thanks! a)Find time the object came to a stop b)the end ...
0
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1answer
12 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
431 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
21 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
40 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 ...
-2
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0answers
36 views

The movement with the speed of light [duplicate]

Light moves at $3\times 10^8$ m/s, but is this speed always so?, imagine if I am in a dark room that is $1$ light year long and I am standing at one extreme end of the room, and there is a powerful ...
3
votes
1answer
54 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
30 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 ...
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3answers
93 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
27 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
64 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
104 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
530 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
68 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
60 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
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1answer
32 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
50 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
41 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
16 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
33 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
49 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?
0
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1answer
31 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 ...
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1answer
46 views

Proper acceleration of a stationary object

What is the proper acceleration measured for a stationary object? is it 9.8 or 0? Thank you.
1
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1answer
105 views

How do I graph acceleration?

I have written some java code for the calculation of some various acceleration and etc. type data. I am now trying to graph that data so I can pull specific data over a time line. The values I have ...
0
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0answers
27 views

Bezier curve and deceleration

I have a question regarding calculation of a bezier curve. I'm programming an app where in there's continuous straight line motion of a vehicle at a constant speed. (Let's call it 'u'). When the user ...
0
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1answer
52 views

Accelerating a glass of a water across a table?

Suppose you have a glass of water on the table (the glass is half-filled, say). You accelerate the glass in a straight line across the table. The effect is that the water inside the glass rises up one ...
1
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1answer
94 views

How are the higher derivatives (jerk, jounce) of position with respect to time used in physics?

I don't see them much in any physics lesson or course, but that's probably because I'm not into physics as much. I can understand why velocity and acceleration are useful, but why would someone want ...
0
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2answers
25 views

Get coefficient of friction given mass, forward force, and acceleration?

I'm aware that this is extremely basic but I've forgotten how to get the coefficient of friction when given a forward force and acceleration. Can someone describe to me the algorithm for solving the ...
1
vote
1answer
43 views

What is the acceleration due to Earth's rotational and orbital movements?

What are the accelerations due to earths spin and orbital motion around the sun? It must be negligible otherwise humans would have been feeling it, are there any instruments that can measure it? would ...
23
votes
4answers
5k views

What would put a harddisk drive (HDD) under 350G's of force?

I always see the label and it says 350G's withstandable. What would put this over 350G's? Is it even possible to hit 350Gs of force to a hard drive?
0
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0answers
20 views

How abruptly would you have to brake to form an almost complete vacuum in the back seat? [duplicate]

Suppose you brake with a car (or any other moving object). As the air inside will rush forward, won't there be a relative dearth of air molecules in the back? So, how strong does the acceleration have ...
-1
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4answers
101 views

Direction of acceleration at highest point

When a ball is thrown vertically upwards, what will be the direction of acceleration at the highest point(where velocity is zero)? Upwards, downwards or arbitrary?
1
vote
1answer
41 views

Smooth collar sliding down smooth shaft [closed]

For part (a), we find that the acceleration of the collar is $6.94~\mathrm{m/s^2}$. In part (b), we say that the acceleration of B with respect to A is $6.94~\mathrm{m/s^2}$, which makes sense. ...
1
vote
3answers
79 views

Gravitational acceleration

'What is difference between free fall acceleration g and gravitational acceleration a?***a is with subscript g.In my textbook it is written that "free fall acceleration = gravitational acceleration - ...
0
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3answers
307 views

What is the use (/ meaning) of $F =ma$? [closed]

I have noticed that Euler's formula for force is useful with a couple of natural forces (at distance), like gravity, that can follow a body any length. If you consider the most common occurrences of ...
0
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1answer
70 views

Total tension in a rope caused by two hanging masses at opposite ends?

Q. A load of bricks with mass m1 = 14.0 kg hangs from one end of a rope that passes over a small, frictionless pulley. A counterweight of mass m2 = 27.8 kg is suspended from the other end of the ...
2
votes
3answers
335 views

Basic question about acceleration [duplicate]

Very basic question. Please show where I'm wrong in the following reasoning. The movement of an object in function of time could be described as $$ x(t) = v t + x_{i} $$ if velocity is constant. If ...
0
votes
2answers
95 views

What force needs to be applied to produce twice as much acceleration as already present in a body? [closed]

Let the current body of mass $m$ be moving with acceleration $a$, produced by applying $F = ma$. So, I thought that if I apply force $F$ again (same magnitude and direction as before), I would get ...
1
vote
2answers
120 views

Why can velocity and acceleration be negative?

Why is speed and acceleration negative when $V_1$ of an object is say 150m/s, $V_2$ is 0 m/s and $\Delta d=0.50\,\rm m$? I found the time it takes which is 0.0033s and the acceleration to be 90909.09 ...
2
votes
6answers
182 views

Why does accelerating electron emits photons? [duplicate]

I have read that accelerating or oscillating electron emits photons. But why and how does it so? And why only photons? There are other bosons like gluons, W and Z bosons, so why does electron emit ...
1
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2answers
80 views

Gravity - change with altitude

Does acceleration due to gravity, $g$, which is calculated by Newton's equation, decrease with altitude? Forgive the silly question.
0
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1answer
24 views

Object moving with 2 linear accelerations

Say I have an object moving with an acceleration of 5 m/s$^2$. At a certain point X, due to some forces, the acceleration of the object changes from 5 m/s$^2$ to 2 m/s$^2$. Would this change in ...
1
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4answers
62 views

Instantaneous acceleration vector toward the concave side of a curved path

Why does the instantaneous acceleration vector of a moving particle always point toward the concave side of a curved path? My college textbooks mention this as something obvious, without further ...
2
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3answers
444 views

Why do non-accelerating objects exert force on each other?

The equation for force is $\vec{F} = m\vec{a}$, where $\vec{a}$ is acceleration. Acceleration is a change in velocity. However, if an object with constant velocity (i.e. 0 acceleration) hits another ...
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1answer
27 views

Which acceleration equations? [closed]

Which equation gives the most accurate answer? $$a=g \sin⁡ α-μg \cos⁡ α\\ a=s/t/t\\ a=2s/t^2 -(2v_0)/t$$ Because i get three different answers. The scenario is a box sliding down on an inclined ...
1
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1answer
208 views

What does this sentence mean?

"The acceleration of free fall on the surface of the Earth is 6 times its value on the surface of the Moon." I interpreted it as: "The acceleration of free fall due to the Earth's ...