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-1 votes
1 answer
103 views

How to Find Trajectory of Particle?

Let’s say I have a particle, and I know all the forces acting on it at every position. (Let’s say the particle is in an electric/gravitational field to simplify the mathematics involved.) Now, is ...
V T Naveen Mugundh's user avatar
0 votes
1 answer
78 views

In $a = dv/dt$, is $a$ the net acceleration? [closed]

While going through the calculus approach to accelerate, we have, $$a = dv/dt, $$ I think, here, v and a should be in the same axis, is my process correct? in a planar motion in two dimensions, it ...
sachin's user avatar
  • 1
0 votes
2 answers
54 views

Magnitude of Acceleration Vector when Speed is Constant

If I observe a change in direction of velocity, but not in speed: What does the acceleration vector look like? I am confused! The difference vector between two vectors of equal length A has a ...
Sylvia's user avatar
  • 123
-2 votes
3 answers
92 views

Why is it wrong to find centripetal acceleration using change of velocity over change of time?

This question asks to find the centripetal acceleration by giving the initial and final velocity over the change of time. As shown, my book combined two rules to find the acceleration. I utterly ...
Manar's user avatar
  • 377
1 vote
3 answers
207 views

Why does a particle initially at rest at origin with acceleration as square of its $x$ coordinate ever move?

Consider a particle initially at rest at origin, with acceleration, $a$, such that $ a(x)=x^2$. Since the particle is at origin, initial acceleration would be 0. It's also at rest initially. Its $x$-...
brainfreeze's user avatar
-1 votes
1 answer
66 views

Interpretation of velocity-velocity and acceleration-acceleration curves

I am parametrizing equations of motion in the form: $$x(t) = x_0+v_{0,x}t\\y(t) = y_0+v_{0,y}t+\frac{1}{2}at^2$$ The parametrized equation with respect to time: $$y(x) = y_0+v_{0,y}\cdot \frac{x - x_0}...
Radek D's user avatar
  • 135
-2 votes
2 answers
98 views

Why does $\vec{a}=\vec{\omega}\times \vec{r}$ as well as the velocity does?

Today I came in class and in one of the problems the teacher used $\vec{a}=\vec{\omega}\times \vec{r}$ which made me very confused because I don't know where it comes from, it seems pulled out of thin ...
Ulshy's user avatar
  • 69
0 votes
0 answers
43 views

Physical and Diagrammatic representation of $a$=undefined when $v$=0 according to $a$=$vdv$/$dx$

$a$=acceleration $v$=velocity $x$=position along x axis $t$=time instant My teacher derived the $a$=$v$$dv$/$dx$ formula as follows Assume a particle at time $t$ is at $x$ position having $v$ velocity ...
Rita Garain's user avatar
0 votes
2 answers
319 views

Why tangential acceleration become 0 when the velocity is max?

I Know that tangential acceleration equal to zero when the circular motion is uniform, but why it is equal to 0 , when the velocity is max or min , because there is no relation between the value of ...
Alia's user avatar
  • 11
-2 votes
1 answer
94 views

What is $V$ in $a$=$V$$dv$/$dx$? [duplicate]

$a$=instantaneous acceleration $V$=instantaneous velocity $x$=position $dx$=small Chang in position $a$=$dv$/$dt$ multiplying numerator and denominator by $dx$,we get $a$=$dv$.$dx$/$dx$.$dt$ now we ...
Aakash's user avatar
  • 161
0 votes
1 answer
41 views

Are terms tangential acceleration and normal acceleration only used for instantaneous velocity?

Are terms tangential acceleration and normal acceleration only used for instantaneous velocity?
Naman Singh's user avatar
0 votes
2 answers
65 views

While derivating equations of motion, why do we replace $v$ as $u + at$?

I was learning about the calculus derivations of equations of motion. After the derivation of $v=u + at$, where $v =$ final velocity and $u =$ initial velocity, came the 2nd Equation of motion. In my ...
Sanyam's user avatar
  • 1
-1 votes
2 answers
64 views

Instantanous and uniform velocity and acceleration [closed]

If the mathemical expression of instantanous velocity is $d/t$, what is the mathematical expression of uniform velocity. If the mathematical expression of instantanous acceleration is $v/t$, what is ...
Meta_Alchemy's user avatar
0 votes
2 answers
701 views

What is the real difference between radial and tangential acceleration?

So in my physics coursebook there are two different kinds of derivation of $\frac{dv}{dt}$ of a particle rotating in a circle. Most of you will know these, they are what is called centripetal/radial ...
Kjell De Mars's user avatar
1 vote
7 answers
281 views

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} ...
Kalcifer's user avatar
  • 329
0 votes
2 answers
268 views

Circular motion equivalent in three dimensions [closed]

Are there equations or even a concept of circular motion/tangential acceleration/centripetal acceleration in three dimensions? Maybe something called "spherical acceleration"? or am I just ...
RhinoPak's user avatar
0 votes
1 answer
87 views

How do I reconcile these two definitions of acceleration?

How do I reconcile these two definitions of acceleration? $$a=\frac{d\bar{v}}{dt}=(\frac{dv^k}{dt}+v^i v^j \Gamma^k_{ij})\bar{e}_k \tag{1}$$ and $$a^k=v^{\small\beta} \nabla_{\small\beta} v^k.\tag{2}$$...
jelly ears's user avatar
0 votes
1 answer
245 views

How to calculate traveled distance with non-constant acceleration in time?

I know this formula $D = vt + \frac{1}{2}at^2$ for calculating the distance given initial velocity, time and acceleration. But what if my acceleration is not static, but increasing exponentially ...
John T's user avatar
  • 853
3 votes
2 answers
156 views

Acceleration in terms of displacement

I am having problems understanding the derivation of acceleration in terms of displacement. The first step is fine: $$a(x) = \frac{\mathrm dv(x)}{\mathrm dt} = \frac{\mathrm dv(x)}{\mathrm dx} \frac{\...
Hugo Lundin's user avatar
2 votes
1 answer
339 views

When exactly does velocity increase or decrease on an acceleration time graph? [closed]

How does the acceleration time graph show if and object is speeding up or slowing down? Is it possible to find the answer without any deep calculations? If yes then how? Like how can I find the ...
Aarya Chavan's user avatar
1 vote
5 answers
148 views

The value of $g$ in free fall motion on earth [closed]

When we release a heavy body from a height to earth. We get the value of $g=9.8 \ ms^{-2}$. Now, I'm confused about what it means. For example, does it mean that the body's speed increases to $9.8$ ...
Junaid's user avatar
  • 27
0 votes
2 answers
507 views

How do I get the velocity $v$ as a function of position $x$ from the acceleration $a$ as a function of velocity?

Suppose that a particle is moving with a non-constant acceleration on the $x$ axis of $$a(v)= Av^2+Bv+C$$ ($A$, $B$ and $C$ are constants) with an initial velocity of 0 on the x axis and an initial ...
FlightSim_Enjoyer's user avatar
0 votes
2 answers
68 views

Motion of free fall [duplicate]

We know that according to law of free falls object, all bodies fall with the same constant acceleration. But in distance formula ($s = \frac12 gt^2$), why the acceleration is just half?
Zeyar's user avatar
  • 25
0 votes
5 answers
1k views

Why do kinematic equations only work with constant acceleration?

People say that the equations are derived assuming a constant acceleration. I just don't see how this is the case. (I am new to calculus.)
AVS's user avatar
  • 314
1 vote
2 answers
129 views

Time derivative of unit velocity vector?

Let's say I have some parametric curve describing the evolution of a particle $\mathbf{r}(t)$. The velocity is $\mathbf{v}(t) = d\mathbf{r}/dt$ of course. I am trying to understand what the expression ...
James Thiamin's user avatar
15 votes
3 answers
4k views

Why does solving the differential equation for circular motion lead to an illogical result?

In uniform circular motion, acceleration is expressed by the equation $$a = \frac{v^2}{r}. $$ But this is a differential equation and solving it gets the result $$v = -\frac{r}{c+t}.$$ This doesn’t ...
Jmh's user avatar
  • 153
3 votes
3 answers
848 views

How do you find the final velocity when acceleration is changing between two values over some distance? [duplicate]

How do you calculate a final velocity of an object when given its initial velocity and the object is accelerating between an initial and final acceleration over some given distance?
Tivity's user avatar
  • 287
0 votes
2 answers
304 views

Why isn't tangential acceleration just always 0?

This is probably a very stupid question but I can't help me. Tangential acceleration is $\vec{a_t}=\frac{dv}{dt}\frac{\vec{v}}{v}=\frac{\vec{v} \cdot \vec{a}}{v} \frac{\vec{v}}{v}$. Since $\vec{a}$ is ...
Quaeram's user avatar
  • 15
2 votes
1 answer
200 views

How to use a piecewise acceleration function to get a position function?

This should be a relatively easy problem but I think I am missing something somewhere. This problem consists of a object that is being thrown into the air at $t = 4s$ at a velocity $v_0$ here is my ...
EzTheBoss 2's user avatar
0 votes
1 answer
62 views

How to determine terminal velocity with speed reduction percentage and constant acceleration?

So I'm developing this game with physics. Every frame, the body accelerates at $+4\,\mathrm{m/s^2}$. However, every frame, the body also sets its velocity to 90% of its original value, basically the ...
Coder2195's user avatar
  • 133
0 votes
4 answers
101 views

Body is accelerating non-uniformly (acceleration is increasing with displacement). How to calculate velocity & time?

If a body is undergoing non-uniform acceleration which is increasing with displacement (It is not necessary that is directly proportional to displacement. It may be proportional to s², 1-s³, √s etc.). ...
Nipun Kulshreshtha's user avatar
1 vote
2 answers
147 views

Determining how long it takes an object to reach a certain speed [closed]

Robotics related. On a linear servo driven rail one can typically set acceleration and maximum move speed. I am trying to determine the amount of seconds it takes the load to accelerate to a certain ...
Eric's user avatar
  • 141
1 vote
2 answers
884 views

Why is position proportional to time squared?

Now I know some of the obvious answers to this, such as if you integrate the acceleration twice, you’ll get time squared, but what I’m really looking for is more of an intuitive answer. One of the ...
Ace's user avatar
  • 11
3 votes
3 answers
2k views

How do acceleration, velocity, and displacement affect/relate to eachother?

I have been wondering this since learning about position, velocity, and acceleration vs time graphs but can't put numbers/equations to it. I know that acceleration acts to change velocity, shown by ...
Curulian's user avatar
  • 169
1 vote
2 answers
111 views

Why isn't tangential acceleration just $a$?

If the tangential acceleration is $\mathrm d|v|/\mathrm dt$ then isn't it just the magnitude of the acceleration of the object because $\mathrm dv/\mathrm dt$ is acceleration?
CatsOnAir's user avatar
  • 139
0 votes
1 answer
112 views

Why intuitively is the tangent vector the derivative of velocity of position with respect to their modulus?

When trying to find the tangential velocity, many textbooks define the tangent direction as one of the following: or Intuitively, why is the tangent vector the derivative of the position with ...
XXb8's user avatar
  • 799
3 votes
2 answers
3k views

Difference between Instantaneous Velocity and Acceleration?

I'm studying the Speed and Velocity chapter. But there isn't anywhere mentioned in my book about clarity for the exact difference between Instantaneous speed and Acceleration. I'm curious to know ...
dopy's user avatar
  • 33
1 vote
2 answers
294 views

What is the time derivative of the linear velocity vector $\vec{v}\,(t)$?

If $\vec{v}\,(t)$ denotes linear velocity, we can then write $\vec{v}\,(t)$ as $|v(t)|\hat{v}$. My question is what is $\displaystyle\frac{d\vec{v}\,(t)}{dt}?$ The answer I have seen to this question ...
ADN's user avatar
  • 39
3 votes
2 answers
285 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: ...
Euler_Salter's user avatar
1 vote
3 answers
90 views

How to deal with functions of kinematic quantities not defined in terms of time?

How do I deal with functions of kinematic quantities which are not defined with respect to time? For instance, given acceleration as a function of velocity or displacement, how would I go about ...
Kishor Kunal's user avatar
0 votes
1 answer
42 views

Is such a situation realistically possible where $v$-$t$ graph is continuous but $a$-$t$ graph is not?

Taking for example $v = \cos(t-1)$ from $t \in [0,1]$ and $v = e^{t-1}$ from $t \in (1,\infty)$ and $t \ge 0$. At $t = 1$, the function shifts from cosine to exponential, but remains continuous since ...
Hoor Tiku's user avatar
0 votes
1 answer
273 views

Can position be derived from acceleration in practice?

We know that acceleration is the derivative of velocity, and velocity is the derivative of position. But does that mean that we can find position from acceleration in practice (as opposed to in theory ...
The Pointer's user avatar
0 votes
1 answer
483 views

Proving that acceleration perpendicular to velocity only changes it's direction [duplicate]

In a recent class, I learned about centripetal acceleration and that if a body moves in uniform circular motion the direction of velocity continuously changes implying presence of an acceleration. My ...
Lalit Tolani's user avatar
3 votes
2 answers
230 views

Generalization of straight line motion under constant acceleration

My question is that, we all know the three equations of straight line motion under constant acceleration, \begin{align} x & =x_{\rm o}+v_{\rm o}\,t+\tfrac12 \mathrm a\,t^2 \tag{1d-a}\label{1d-a}\\ ...
Sohaib Ali Alburihy's user avatar
1 vote
1 answer
425 views

Expressing acceleration in terms of velocity and derivative of velocity with respect to position

we know that $$a = \dfrac{dv}{dt}$$ dividing numerator and denominator by $dx$, we get $$a=v\dfrac{dv}{dx}$$ provided that $dx$ is not equal to zero or instantaneous velocity not equal to zero when I ...
Lalit Tolani's user avatar
7 votes
6 answers
2k views

Can acceleration depend linearly on velocity?

Is it possible that acceleration may vary linearly with velocity. Is it practically possible, if so is there a practical example of it? By integration I was able to verify that for the above case to ...
Gurjot Singh's user avatar
1 vote
3 answers
62 views

Motion in a plane situation

There is something weird I find about the following situation. Suppose a particle has the $X$-coordinate $= 2+2t+4t²$ and $Y$-coordinate $= 4t+8t²$. So it's velocity in $X$ is $2+8t$ and velocity in $...
Qwerty's user avatar
  • 45
0 votes
2 answers
73 views

Confusion Unit of Acceleration

I have been reading Newtonian mechanic but I got confuse in defining the unit of acceleration that "Why is the unit of acceleration $m/s^2$"?
Sahad Ahmad's user avatar
0 votes
3 answers
165 views

Power and work contradiction

A body is starting from rest. A force is acting on it for a short period of time. In that given time, power delivered to it at any instance $t$ is given $$P = F \cdot v_1 = ma \cdot v_1 = mv_1^2/t,$$ ...
Priyesha Jha's user avatar
2 votes
1 answer
518 views

How to determine the minimum "Arrival Distance" given a maximum velocity, acceleration and jerk along with an initial velocity and acceleration?

Problem Given the following: $A$ - maximum acceleration. $J$ - constant jerk (the rate of change of acceleration). $v$ - initial velocity. $a$ - initial acceleration (where, in practice, $a ∈ [-A, A]$...
mindTree's user avatar
  • 121

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