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Questions tagged [displacement]

The tag has no usage guidance.

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2answers
49 views

Vector Significant Figures [on hold]

I was answering a question and I was told that I should observe proper significant figures. The question is: A car travels 9.00 Km East and then 6.00 Km, 30.0° North of East. Find the displacement of ...
0
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4answers
97 views

What does a negative acceleration mean? Is the object slowing down, changing direction, or both?

I am confused about such things as negative velocity, acceleration, and displacement and what the negative indicates.
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0answers
20 views

Phase difference between displacement wave and pressure wave in longitudinal waves

As the Mathematical treatment yields, the pressure wave leads the displacement wave by $\frac{\pi}{2}$. But I want to ask why is it so? According to me, supposing if the displacement wave is a sine ...
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2answers
65 views

Why is work done a dot product of force and distance?

Suppose force is applied on an object at an angle theta and the block moves for some distance along x axis I understand that we take x component of ...
0
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2answers
45 views

Can displacement be negative after calculation?

Regardless of the positive or negative, doesn't the number determine the total displacement and not the sign in front of the numbers?
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1answer
53 views

Are there any formulas that calculate the stopping distance of a car on different surfaces that include deceleration?

I already found the formula $d = v^2/2\mu g$ where '$v$' is for velocity, '$\mu$' is for the coefficient of friction between the tires and the road surface, and '$g$' is the acceleration of gravity. ...
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3answers
89 views

What makes displacement a vector?

Displacements are vectors because they add like vectors is the answer. It is also an experimental fact. Though rotations are displacements but not vectors. Is there any more fundamental or intuitive ...
0
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1answer
32 views

Conceptual explanation: Finding revolutions over a given time interval

The following question from NJCTL was assigned for me as homework. It is not a heavy computational problem, but rather, a conceptual one. I reviewed the meta guide regarding these types of questions ...
0
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1answer
47 views

In the equation for acceleration (with known $v$, $u$ and $s$) why velocity is squared and displacement is multiplied by 2? [closed]

In the following equation $$a = \frac{v^2 − u^2 } {2s} ,$$ where $v$ is the final velocity, $u$ is the initial velocity, and $s$ is displacement. Why is velocity squared and displacement multiplied by ...
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2answers
33 views

Confusion on Horizontal & Vertical Components of a Parabolic Motion

This was a question I found about projectile motion, the question was what's the bike's speed when it took off. Using $S=ut + 0.5at^2$, the time taken to reach the ground is $0.505 s$, they used ...
0
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0answers
43 views

Acceleration as the second derivative of displacement function

Let $x$ be displacement as a function of time $t$ and some other physical quantity $k$ such that $ x = f(t,k) $ Now, 1) Will the acceleration $a$ be $\frac{\partial^2 x}{\partial t^2}$ or $\frac{d^...
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2answers
31 views

What's the relation between acceleration, position and angular velocity?

I just encountered a problem involving lift and oscillations where I found the following differential equation: $$\ddot y = -\frac{ \rho gA}{m}y = -\omega^2 y$$ What's the relation between $\ddot y$, ...
3
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4answers
169 views

Different expressions for distance & displacement : $\int$$d$$|\vec r|$, $\int$$|$$d$$\vec r$|, and $|$$\int$$d$$\vec r|$

I came across these expressions in my book. And the book says that all these are different from each other. The expressions are : $\int$$d$$|\vec r|$, $\int$$|$$d$$\vec r$|, and $|$$\int$$d$$\vec r|$ ...
0
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1answer
35 views

Representing a wave

I don't know how relevant is asking this but We know that we represent waves by displacement, velocity etc.What about area vectors? I mean what about representing a wave by area vectors or even volume?...
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0answers
18 views

Frequency modes of the rectangular shell

The shapes of three natural modes having the frequencies $w_1$, $w_2$, $w_3$ of the rectangular shell are presented in the figure. The exciting pressure $p(t)$ applied uniformly all over the one side ...
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2answers
73 views

Why is work defined with respect to distance rather than time? [duplicate]

The common way of finding the work done on some object is by applying the equation: force*displacement. However, suppose we apply a force of F newtons on an object of mass M for a duration of T ...
0
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1answer
113 views

How to know what the area under curve represents?

Is there a way to find out what the area under the curve represents? For eg. If i gave you a graph of $v$ with respect to $t$ would you be able to tell me what the area under the curve represents ...
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3answers
127 views

Hooke's Law: Is the extension of a spring the same as its displacement?

This question might make no sense, but I'd like to ask it anyway. The elastic potential energy of a spring is the area under the force-extension/compression graph. The work done on a spring is ...
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2answers
42 views

How to study the work done by a varying force on a system moving in two dimensions?

My book states that: $$W=\int_{x_i}^{x_f}{F_x dx}$$ We can calculate the area under the curve representing force as a function of position when the displacement and the force are in one direction ...
3
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2answers
156 views

Does Euler number $e$ have a role in kinematics?

Euler number $e$ is often explained with the example of compound continuous interest. I was wondering if it could also be illustrated with an example about the displacement of a body (although not an ...
3
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2answers
86 views

Why work definition involves displacement?

$$W=\left\Vert\vec{F}\right\Vert \left\Vert\Delta\vec{r}\right\Vert \cos{\theta}$$ A greater magnitude force will have a greater influence than a smaller magnitude one when they have the same $\theta \...
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1answer
75 views

Relation between strain and velocity

The strain tensor writes $\epsilon_{ij}=\frac{1}{2}\Big(\frac{\partial u_i}{\partial x_j}+\frac{\partial u_i}{\partial x_j}\Big)$ with $u_i$ the displacement in the $i$ direction. Then $\frac{\...
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1answer
111 views

Strain gauge vs linear variable displacement transducer

For measuring deformation experiments, it seems that strain gauges and linear variable displacement transducers (LVDT) are commonly used. If the material exhibits geometric linearity, then couldn't we ...
3
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1answer
185 views

I need to find the drag coefficient of a pendulum bob [closed]

Is it possible to find the drag coefficient of a pendulum bob from the damping caused on it during swinging. I will be able to measure its displacement from the point of origin and plot it against ...
1
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1answer
82 views

Displacement current quantum mechanical interpretation?

while there are quite many classical explanations of displacement current to make Maxwell's equations work, see e.g. here: Displacement current - how to think of it , it sounds just a little bit like ...
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2answers
69 views

Is the direction of average velocity the same as that of average acceleration and that of displacement?

Average velocity is defined as: $\vec{\Delta v} = \frac{\vec{\Delta r}}{\Delta t}$, and average acceleration as $\vec{\Delta a} = \frac{\vec{\Delta v}}{\Delta t}$. It is apparant from these ...
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2answers
64 views

Are distance and displacement always frame independent?

I'm aware that distance and displacement, both are independent of reference frames, when the two frames are stationary wrt each other. Because the actual distance (or the shortest distance) between ...
1
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2answers
29 views

Displacement using work energy principle

How do you use the work energy principle to find the displacement of an object. With of course the mass, speed and friction forces given?
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2answers
67 views

Boundary condition: displacement

I have a controversial case. I have a rod, which is fixed from one end (constraint). From another end, I apply a compressive force, by pressing the rod down. So in a way I have a constraint, but at ...
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2answers
62 views

What is the displacement between $t=1$ and $t=8$? [closed]

Given the graph above, what is the displacement between $t=1$ and $t=8$?I thought this was a straight forward questions: It's supposed to be the area under the curve. Moving the time axis up to where ...
1
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0answers
50 views

Why are all the other sub-displacements included into to the total displacement? [closed]

Problem: During a jaunt on your sailboat, you sail $5\,\mathrm{km}$ east, then $5\,\mathrm{km}$ southeast, and then an additional distance in an unknown direction. Your final position is $20\,\...
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3answers
38 views

Travelled displacement - how do we take care of the possibility that it might be negative?

so this is a very basic question but I can't really find a full answer. So let's assume we have a point of mass $m$ travelling along the x-axis with a acceleration a. The travelled displacement is: $...
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3answers
1k views

What does the 'displacement' refer to in the definition of work?

The definition of work given in books is The work is said to be done by a force on a body, when the body is moved by the force through some 'displacement'. Now let a body of mass $m$ at rest. When a ...
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1answer
2k views

Why is work scalar and the dot product of force and displacement?

I asked many people why work is scalar. But the questions and the answers just cycles. My question : Why is work a scalar quantity? Their answer : Because it is the dot product of Force and ...
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2answers
455 views

Displacement vector vs position vector

Below are my attempted definitions of the two terms. Are these correct and do they clearly distinguish between the two terms? My understanding is that the displacement vector comes first and that is ...
0
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1answer
274 views

Spring Displacement

I am having trouble understanding the sign/direction of displacement for the equation F=-kx. I am not going to elaborate on what the specific problem is that goes along with this visual since that's ...
0
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1answer
396 views

Sign of work done by friction

In Goldstein's classical mechanics (3rd ed.) we read: "The independence of W12 on the particular path implies that the work done around such a closed circuit is zero,i.e. $$\oint \textbf{F}.d\...
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1answer
42 views

Orthonormality of displacement operators

I'm trying to prove that displacement operators are orthonormal in quantum mechanics, e.g.: $$\text{Tr}\{D^{\dagger}(\alpha)D(\beta)\} =\pi \delta^2(\alpha - \beta)$$ I used the completeness property ...
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3answers
229 views

What is the “displacement” of the object in the definition of work?

Work in physics is mathematically defined as force $F$ applied on an object multiplied by the displacement $d$ it covers in the direction of the force. In a system where, a restrictive force exists ...
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2answers
2k views

Calculating Intitial Position given the ratio between the last two seconds of free fall for 1D motion

I've tried this problem in multiple different ways and can't seem to come up with an acceptable answer. The question is, A rock is dropped from the top of a tall building. The rock's displacement ...
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1answer
89 views

What exactly is “displacement” and “velocity”? [duplicate]

I'm finding two different definitions for what the displacement of an object is: 1) How far the object is from a starting point in a specified direction (direction represented through a straight line ...
0
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2answers
75 views

Is my total work infinite?

Suppose I'm in space. I push a ball with a force. Then it will start to move and continue to move forever. So the distance traversed by the ball is infinite. So we know, $$W=F × S =F × Infinity ...
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3answers
83 views

Is the formula for work $W= \vec{F}\cdot \vec{s}$ or $W=\int_C \vec{F} \cdot d\vec{s}~$?

I'm pretty much not so much introduced to calculus (I am grade 11 of India and they teach integration part of basic calculus by the end of grade 12) so I would be glad if the answer will be much more ...
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0answers
31 views

Lattice to continuum transformation in one dimension (arbitrary range interaction)

Please help me convert the ionic displacement $u_l$ of the $l^{th}$ ion to a continuous field $u'(y)$ in the following problem. I am trying to derive the Hamiltonian of a 1-D lattice (spacing $=n_0^{-...
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2answers
80 views

How do we know that force is a vector?

With displacement, our axoims and 'laws' of vectors work because that is how we designed vectors to work, as it seems obvious that displacement would follow the 'triangle law of vector addition', but ...
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4answers
85 views

Why don't we use $F=−kx$ while finding a spring constant?

A block of mass $m$ is attached to a vertical spring in equilibrium, and is stretched a distance $d$. As Hook's law is $F=-kd$ If I take $y$-axis to be positive upward, the net force in the $y$ ...
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3answers
66 views

Why can the deformation of a spring at a given point of the spring be considered directly proportional to the relative distance of the point?

Hello i have been studying differential equations and in one example my professor tries to deduce the partial differential equation that describes the longitudinal displacement on a elastic, ...
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2answers
2k views

Distance and Displacement from a velocity vs. time graph

My teacher is saying that the distance covered will be equal to the area of the trapezium in the graph, but the displacement will be equal to the area of the triangle (with purple hypotenuse). I ...
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1answer
203 views

Integrating position/displacement with respect to time

We know that we get displacement if we integrate velocity with respect to time. But from my curiosity I am now wonder, what will I get if I integrate position/displacement with respect to time?
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9answers
1k views

Why is small work done always taken as $dW=F \cdot dx$ and not $dW=x \cdot dF$?

I was reading the first law of thermodynamics when it struck me. We haven't been taught differentiation but still, we find it in our chemistry books. Why is small work done always taken as $dW=F \cdot ...