All Questions
Tagged with acceleration kinematics
77 questions
20
votes
5
answers
133k
views
How to get distance when acceleration is not constant?
I have a background in calculus but don't really know anything about physics. Forgive me if this is a really basic question.
The equation for distance of an accelerating object with constant ...
- 1,527
10
votes
3
answers
59k
views
How can an object's instantaneous speed be zero and it's instantaneous acceleration be nonzero?
I'm studying for my upcoming physics course and ran across this concept - I'd love an explanation.
- 203
8
votes
3
answers
7k
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Integrating radial free fall in Newtonian gravity [duplicate]
I thought this would be a simple question, but I'm having trouble figuring it out. Not a homework assignment btw. I am a physics student and am just genuinely interested in physics problems involving ...
- 93
2
votes
1
answer
2k
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Are velocity and acceleration smooth quantities?
My thinking:
acceleration corresponds to a force which is instantaneous, so the acceleration of a rigid body can be rather spiky (non-smooth)
velocity (angular velocity) describes the ratio of ...
- 123
10
votes
6
answers
3k
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Physical intuition for higher order derivatives
Could somebody give me an intuitive physical interpretation of higher order derivatives (from 2 and so on), that is not related to position - velocity - acceleration - jerk - etc?
- 202
0
votes
2
answers
2k
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Tangential acceleration in circular motion?
A lot of my problems have objects moving in circular paths with tangential and normal components of acceleration.
If the tangential component is non-zero though, the speed is changing so the radius ...
- 2,039
24
votes
7
answers
10k
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Can an object *immediately* start moving at a high velocity?
What I mean is, suppose a ball is fired from a cannon. Suppose the ball is moving at 100 m/s in the first second. Would the ball have started from 1m/s to 2m/s and gradually arrived at 100m/s? And is ...
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16
votes
3
answers
3k
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How does anything move? [duplicate]
So in order for two things $A$ and $B$ to move apart, for example, relative to each other, $B$ can be set into motion away from $A$. This means that we have to increase $B$'s velocity and therefore ...
9
votes
5
answers
8k
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Is there a scalar acceleration?
The magnitude of Velocity is simply Speed.
On the other hand, the magnitude of Displacement seems to be a simpler idea than Distance.
And the magnitude of Acceleration is not the change of Speed over ...
25
votes
7
answers
12k
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Zero velocity, zero acceleration?
In one dimension, the acceleration of a particle can be written as:
$$a = \frac{dv}{dt} = \frac{dv}{dx} \frac{dx}{dt} = v \frac{dv}{dx}$$
Does this equation imply that if:
$$v = 0$$
Then,
$$\...
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17
votes
5
answers
6k
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Velocity is to speed as acceleration is to ________? [duplicate]
Vectors give both magnitude and direction, whereas scalars can be thought of as magnitude without direction. So, velocity is a vector since it is speed with direction. Similarly, what is the scalar ...
user209860
2
votes
9
answers
111k
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Why isn't the acceleration at the top point of a ball’s journey zero?
When I shoot a ball vertically upward, its velocity is decreasing since there is a downward acceleration of about $9.8\,\mathrm{ms}^{-2}$.
I have read that at the top most point, when $v = 0$, the ...
- 1,790
0
votes
5
answers
16k
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tangential acceleration for uniform circular motion
I understand that circular motion is defined by 2 components of acceleration, one tangential and one radial and their resultant is what causes circular motion.
I am confused though as to why it is ...
- 137
6
votes
10
answers
291k
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What does the magnitude of the acceleration mean?
I am a little confused as to what the magnitude of acceleration is and what it means.
- 93
2
votes
1
answer
9k
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Kinematics with non constant acceleration
A particle experiences an acceleration described by
$$
a=kx^{-2}
$$
where x is the displacement from the origin and k is an arbitrary constant.
To what value does the velocity v of the particle ...
- 123
1
vote
1
answer
113
views
What will be the trajectory of the given motion [closed]
If it is given that component of acceleration perpendicular to the velocity of a body has a constant, non-zero magnitude, how can we mathematically prove that the trajectory of the body will be ...
- 212
1
vote
7
answers
293
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I'm having trouble understanding the intuition behind why $a(x) = v\frac{\mathrm{d}v}{\mathrm{d}x}$ [duplicate]
I was shown
\begin{align}
a(x) &= \frac{\mathrm{d}v}{\mathrm{d}t}\\
&= \frac{\mathrm{d}v}{\mathrm{d}x}\underbrace{\frac{\mathrm{d}x}{\mathrm{d}t}}_{v}\\
&= v\frac{\mathrm{d}v}{\mathrm{d}x}
...
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16
votes
5
answers
3k
views
What is the best path for a given initial and final state?
I am trying to calculate an efficient acceleration curve given starting and final positions and velocities. I'm assuming no friction, and that the acceleration can be applied in any direction at any ...
- 163
15
votes
4
answers
396
views
Problems in the relation $a=v\frac{\mathrm{d}v}{\mathrm{d}x}$
We all know $a = \frac{\mathrm{d}v}{\mathrm{d}t}$.
A little application of the chain rule leads to the relation
$$a=v\frac{\mathrm{d}v}{\mathrm{d}x}$$
But the above equation shows that $a=0$ whenever $...
- 449
14
votes
4
answers
2k
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Why doesn't constant acceleration give me total displacement?
I started learning 1D kinematics and learnt definitions of constant velocity and constant acceleration. I thought that if a particle is changing its velocity uniformly then it has constant ...
- 177
9
votes
2
answers
2k
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Non-Constant Acceleration due to Gravity
Recently, I had the first physics lab for my university physics course. This lab was fairly simple, as we were merely using a computer and a distance sensor to graph the position, velocity, and ...
- 93
6
votes
4
answers
838
views
How can I write the vector form of this equation, $a = vdv/dx$?
My Physics teacher was deriving the 'Work-Energy Theorem' for a single particle in the class; where after doing the vector addition of all the forces acting on the particle, he put the resultant of ...
- 65
4
votes
1
answer
258
views
Special Relativity and Accelerated Reference Frames
I am looking for a good reference on how to treat accelerating reference frames in special relativity, particularly with respect to accelerating linear motion and circular motion. Are there any that ...
3
votes
2
answers
43k
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Difference between Speed and Velocity
What is the difference between Speed, Velocity and Acceleration? Could any one describe it pictorially?. I am more over confused even after investigating many times. I am unable to relate myself ...
- 133
3
votes
2
answers
312
views
Motion with constant speed and constant acceleration magnitude
I was reading this and this posts. From what I gather
In 2D: Constant speed $||\dot x||=const$ and constant positive magnitude of the acceleration $||\ddot x|| = const$ imply circular motion.
In 3D: ...
- 247
2
votes
2
answers
15k
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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 ...
- 21
2
votes
4
answers
8k
views
How is acceleration measured if there is change only in the direction of velocity & not magnitude?
The formal definition of acceleration is
It is the measure of how fast the velocity changes with respect to time.
Now, when the magnitude of velocity changes, acceleration $$\vec{a} = \frac{d \...
user36790
1
vote
3
answers
2k
views
Difference between different radial and centripetal accelerations:(Doubt)
In cylindrical coordinates I had derived the acceleration as :
for the first component of acceleration, what is the difference between radial and centripetal ?
- 29
1
vote
3
answers
2k
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How to approximate acceleration from a trajectory's coordinates?
If I only know $x$- and $y$- coordinates of every point on a trajectory without knowledge of time information, is there any way to approximate Cartesian acceleration angle at each point? Time interval ...
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1
vote
1
answer
12k
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What is the difference between negative acceleration and decreasing acceleration?
According to Reisnick and Halliday, retardation is the acceleration in the negative direction of time axis ie. opposite to the motion. Decreasing accleretion is the decrease in the magnitude of time ...
user36790
1
vote
4
answers
25k
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Deriving equations of motion using integration
Please refer to my school textbook pg48 (of the book, and not the pdf counter) here: http://ncertbooks.prashanthellina.com/class_11.Physics.PhysicsPartI/ch-3.pdf
My doubt is in this context: (right ...
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1
vote
2
answers
3k
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In 1D why are vectors, such as, e.g., velocity $v$ and acceleration $a$, not written with a vector arrow?
In my textbook instantaneous velocity and acceleration are wrote only as $v$ and $a$ in the chapter of One dimensional motion.
Instead, in two dimensional motion chapter they are written with the "...
1
vote
3
answers
88k
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How to find stopping distance of a car? [closed]
I am trying to calculate the minimum stopping distance of a car once the brakes are applied. I know that $F = ma$, and the braking force is $F = \mu N = \mu m g$, so
$$a = \mu g.$$
Next, by applying ...
- 19
0
votes
4
answers
672
views
Question about $a = v\ \mathrm dv/\mathrm dx$
Consider $\vec{v}$ Now differentiating this w.r.t time,
$$\vec{a} = d/dt( \vec{v}) = \vec{v}(d\vec{v}/dx)$$
Now this multiplication of vectors obviously makes no sense. This along with the fact that ...
- 1,106
20
votes
5
answers
6k
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Why do these two ways of understanding constant acceleration give different results?
I have a question pertaining to the concept of acceleration and it's formula - Both seem to give me different answers.
I was asked:
A train is moving at a velocity of $20\ \mathrm{m/s}$. It hits ...
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15
votes
5
answers
8k
views
How to brake 'beautifully'?
Sometimes when I'm driving my car, I play a "game" against myself in which I try to minimize the deceleration felt by passengers (including myself) while still braking in a reasonable short space. I ...
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13
votes
4
answers
3k
views
What would qualify as a deceleration rather than an acceleration if speed is unchanged?
The instantaneous acceleration $\textbf{a}(t)$ of a particle is defined as the rate of change of its instantaneous velocity $\textbf{v}(t)$: $$\textbf{a}(t)=\frac{\mathrm{d}}{\mathrm{d}t}\textbf{v}(t)....
- 27.2k
13
votes
7
answers
3k
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Can we divide a vector by another vector? How about this: $a = vdv/dx?$
My physics teacher told us that we can’t divide vectors, that vector division has no physical meaning or significance. How about this: $$a = vdv/dx.$$
It says acceleration vector equals velocity (as ...
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7
votes
2
answers
25k
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How to remove gravity component from accelerometer $X$, $Y$ readings?
So I have an accelerometer which I am wanting to use in an IMU.
When the device is tilted but stationary I want the x, y values to be 0, so effectively negate the effect of gravity along the x and y ...
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6
votes
5
answers
77k
views
If an object moved 5 meters in a second, how can its velocity be 10 m/s? [duplicate]
On physicsclassroom.com, an assignment gives data for an object experiencing acceleration:
This is the corresponding chart for the object's velocity:
At $0$ seconds the position of the object is $0$...
- 61
6
votes
2
answers
1k
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Terminology for time derivative of speed (not velocity)
Is there any standard terminology for the derivative of the magnitude of velocity with respect to time (suitable for use in first-year Calculus)? The word ‘acceleration’, in its technical sense, is ...
- 201
5
votes
2
answers
330
views
How long does it take to optimally change position and velocity?
A spaceship moving in two dimensions is at position $(x, y)$ and has a velocity $(v_x, v_y)$. It also has a maximum acceleration $a_{max}$. Its goal is to be at position $(x', y')$ with a velocity of $...
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5
votes
4
answers
2k
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Is there any such thing as a change in acceleration (ex: 3 m/s/s/s)? [duplicate]
If there exists something like that, then in $distance/time/time/time$, how is it expressed?
- 171
4
votes
3
answers
794
views
Why is harder to accelerate object at higher speeds if speed is relative term?
Why is it harder to accelerate object at higher speeds (even if resistance forces dont exist) if speed is a relative term?
Object speed is relative term, it depends from wich frame of reference we are ...
- 730
4
votes
2
answers
4k
views
Formulas for ball rolling in a bowl?
I'm developing a program where I've a ball/sphere rolling in a bowl from the side at top, till the center at bottom, and I'm trying to get the formulas for:
The rotation angle and the position of the ...
- 141
3
votes
5
answers
2k
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 ...
- 33
3
votes
4
answers
2k
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In perfect vacuum (no external force), if I apply a small amount of force to a body, will it continue to accelerate forever?
According to the equation $F = ma$, the greater the force applied to a body, the greater its acceleration. But in a place where there is no gravity or any other kind of external force, if I apply a ...
- 227
3
votes
1
answer
1k
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Confusion in coordinate transformation of acceleration vector
Consider this notation for vectors:
$A_{cb}^{d}$ is the $A$ vector (velocity,acceleration, angular velocity or ...) of $b$ coordinate frame w.r.t. $c$ frame presented in $d$ frame axis.
I know when we ...
- 31
3
votes
4
answers
9k
views
What is the difference between uniform velocity and constant velocity? [closed]
I think that uniform velocity implies constant speed but not constant direction. while constant velocity implies constant speed without any changes in direction.
Both tell us that there's no ...
- 41
3
votes
2
answers
2k
views
Utilizing maximum acceleration $a$ for displacement $d$ with initial velocity $v_0$ and final velocity $v_1$
Problem
My goal is to move an object from point a to b (displacement $d$) as fast as possible utilizing the maximum available acceleration $a_{max}$, taking into account the initial velocity $v_0$ ...
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