Questions tagged [speed]

Scalar quantity which is the magnitude of velocity.

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What is the displacement time graph for this object which is in x-y plane going in sine wave like path from A to B.Also can velocity constant inpath?

[![Path of object][1]][1] The path is from A to B in sine wave curve while the displacement is straight line.So how displacement is calculated for graph purpose here [1]: https://i.stack.imgur.com/...
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Earth colliding into planet-sized object faster than speed of light [duplicate]

Imagine the following scenario: Earth is travelling in one direction at just over half the speed of light Another planet-sized object is traveling in the opposite direction towards Earth, also at ...
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Does speed of electrons decreases when they pass through resistance?

What type of energy does battery supply to electrons , as I read battery increases KE of electrons but in load if they lose it then speed will decrease and current will decrease after coming out of ...
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Speed of sound in a real gas

The speed of sound in a real gas is $C = \sqrt{ZkRT}$, where $C$ is the speed of sound in the gas, $k$ is adiabatic gas constant $={C_p}/{C_v}$, $R$ is the gas constant and $T$ is gas temperature in ...
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In the case of a free wave function, does $|p| = E_k = 0 \mapsto |v|=0$?

This answer indicates that "it is not possible to talk about a particle 'stopping' or being 'stopped' in any meaningful or non-contrived sense" because of the Heisenberg indeterminacy ...
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Calculate efficiency from discrete power, time and distance

I have a sequence of points from GPS and OBD for some vehicles. Each point has the instantaneous power of the engine $(P)$, the time elapsed from the last points $(T)$ and the distance traveled from ...
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Why does kinetic energy increase quadratically by speed and linearly by mass? [duplicate]

I never found a simple explanation to kinetic energy and wonder if this one makes sense. In the following example, I'll try to provide an intuitional approach for calculating kinetic energy of an ...
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Is possible to achieve an infinite speed in real life? [closed]

Is possible to achieve an infinite speed in real life? I know beforehand that relativity theory forbids anything from travel faster than speedlight, so please stay with reading the full question first ...
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Why spinning bullet is more stable in air?

I found out about stagnation point recently, it is an arbitrary edge or point where the stream of air molecules parts. I was wondering could a spinning bullet affects the stagnation point to improve ...
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Is the sound speed and density relation different for compressible and incompressible media?

I'm studying "speed of sound in air" and I read that sound speed is inversely proportional to the density of the medium. However, I also know that sound travels fastest in solids, and that ...
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Average speed / Velocity

We know that in kinematics we have the concepts about "average speed". By definition the average speed is the total of the distance divided by time, but I still don't get it what is the ...
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Why does sound travel faster in helium than in air? [duplicate]

Sound wave travel faster in solid than in liquid, and travel in air with the slowest speed because solid is denser than liquid and liquid is denser than air. So, sound wave speed should be faster in ...
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We say that speed of sound is fastest in solids because particles are closely packed to each other, but why is speed more in hot air?now,they are far

I know we say that the speed of sound is most in solids because the particles are closely packed to each other,so,the energy transfer can take place easily compared to when they are farther in air or ...
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Why does the amplitude not increase the speed of the sound wave?

The way I see it,if there's a set up A which has 5 particles and another set up B which also has 5 particles,and assuming everything else is same in these set up,like distance between particles etc,if ...
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Would paradoxes arise if the one-way speed of light weren't $c$?

Introduction Let me start by saying that this is not a question about how to measure the one-way speed of light (OWSOL). It's about the physical implications of the idea that this speed is merely ...
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Why does the time of rotation only rely on the angle and the length of the string?

My question is in the title. How does the time of rotation in this example have nothing to do with speed? Intuitively, if the bob is going at a faster constant speed the time of rotation would be much ...
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If I had a car which could go with a speed of light, could I drive it at night? [duplicate]

Just theoretically, when I turn on the lights in my super fast speed of light car, would I see the road if the light can't go faster than my car?
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Will you see distance contraction inside the space ship at near light speed?

We know that distance to destination contracts for a passenger in a spaceship traveling at near the speed of light. If a spaceship is traveling at 0.865C to the outside observer, then the distance to ...
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Does gravity slow down sound (does sound travel faster downwards than upwards)?

I have read this question: So assuming the heavier planet has the same atmosphere as Earth, and that we can treat the atmosphere as an ideal gas, the speed of sound on the heavier planet would be the ...
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Speed of energy in a pulse wave

Consider a Dirac pulse giving rise to a wave propagating in a uniform generic medium. Since all mediums are dispersive and lossy except for vacuum, the frequency components of the pulse will travel at ...
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Could the kinetic energy formula $E=\frac{1}{2}mv^2$ be derived by the Pythagorean theorem?

The kinetic energy formula $E=\frac{1}{2}mv^2$ relates energy to the square of the velocity. There are many nice explanations on this site which deal with this fact. But could we give an explanation ...
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Can crooked surfaces alter speed messurement using a laser?

this might be an unconventional question yet I think the physics community would be the one to help here. Please hear me out. So my problem/question: I drove into a laser speed trap with my motorcycle ...
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Is it possible to measure the electric current speed through the wire by this method?

This method is very simple but I am not sure if it would provide accurate measurements.The current electrons deriving from the battery should have some speed and in that way should interact with the ...
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With what speed does a thermal front travel through a solid?

The heat equation provides theoretical temperature distributions as a function of space and time. Take for example an infinitely long rod that is suddenly heated up at $t = 0$ at its end $x = 0$. The ...
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Two waves having same wavelength

Is it possible for two wave to have same wavelength but different speed and frequency? According to $C=λ×f$, if wavelength is constant, then frequency must be proportional to speed. My explanation is :...
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Distance given two velocities

I have a home trainer that is connected to an application that I am writing which needs to calculate a distance traveled given the speeds that the trainer is sending. As such, every second, the ...
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1/velocity for higher dimensions

I have a somewhat basic question. I am sorry if it trivial. Denote the velocity by $v=\frac{dx}{dt}$ suppose that $x \in \mathbb{R}^n$ and I want to parametrize $t$ in $x$ and compute $\frac{dt}{dx}$. ...
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Does the mass in $E=mc^2$ change with the speed of the mass? [duplicate]

I was involved in a discussion on Quora about going faster than the speed of light and I pointed out that $E=mc^2$ implies that the faster the mass goes the more energy you would obtain from it. One ...
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At what speed would a wind affect a bullet? [closed]

Firing a gun loaded with the fastest bullet (.220 Swift 1,422m/s or any bullet that is super fast and excellent aero dynamics) in a close range (2cm) from the tip of an air blower. What would be the ...
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Why does the value of the escape velocity approach 0?

I am a little confused about escape velocity. Does the escape velocity always approach 0 as we go to an infinitely far distance even if there isn't any friction? If so, why does it approach 0? Shouldn'...
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How does the world's most accurate accelerometer work?

i'm having trouble finding any sources that describe what the most accurate accelerometer is. I'd like to know what it is and how it works.
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How to run faster? Velocity vs foot on floor

I was wondering how you can increase your running speed depending on how you set your foot on the floor. In other words, how does the position of the foot area on the floor influence the speed/...
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Calculate distance with variable acceleration

I haven't studied math in many years, so this might be trivial but I would appreciate any help nonetheless. I want to calculate the distance it takes for a vehicle to reach a specific speed. I have ...
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What limit rocket final speed if there is no drag?

If thrust is constant and drag dont exist, speed goes to infinity or in relativistic physics to speed of light. Even in relativistic theory mass of rocket increase with speed that will just reduce ...
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Will the mass affect the speed of the toy car?

Let’s say you have to calculate the speed of a toy car. However you will be adding weights onto the car. The car will be going up a rank with a 20 degree angle. Will the car slow down? If yes why?
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A rolling stone on a rollercoaster

A ball rolls from point $A$ ($v_0 = 0 \; m / s$) to the right along a friction-less path. We can then calculate the speed of the ball at the points $B$ and $C$ using the law of conservation of ...
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Is the derivative of the magnitude of a position vector the speed? Is the integral of the speed the magnitude of a position vector?

I'm reading a book titled "Introduction to Mechanics" by Kleppner, and I came across an example: A bead moves along the spoke of a wheel at constant speed $u$ meters per second. The wheel ...
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Is velocity a vector quantity? [closed]

I've read that velocity is a vector quantity. Then why do most of the people when stating the velocity of an object never use direction? Most of them usually say that 'a car is moving at a velocity of ...
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Units of Linear Speed in a Circular Motion

During Uniform Circular Motion, the linear speed of the particle is defined as the radius times the angular speed. $$ v = r\omega $$ The units of linear speed is meters/second (m/s). But the units of $...
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Why the things small seemed to move faster?

*This question might had to do with the introduction of the absolute scale. Consider the planet that travel around the star, the length for it to complete the orbit was in the range of the years.(The ...
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Does increase in relativistic mass with speed violate principle of relativity?

From special relativity we know that, $$ m = \frac{m_0}{\sqrt {1-\frac {v^2}{c^2}}} $$ where, $m$, $m_{0}$ and $v$ are the relativistic mass, rest mass of the object and speed relative to the observer ...
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Why do we get a shock from electric wire instantly? [duplicate]

As we know the drift velocity of electrons in conductors is very low and it is about a few millimetres per second. Now suppose I hold one end(naked) of a wire which is not connected to any source. ...
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Cam waves travelling at same direction interfere?

Can two waves travelling in same direction interfere?
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If traveling with relativistic speeds can observer find space denser than normal?

I know that outer space contains few particles per cubic meter, but I am curious if travelling that fast for our brave traveller all of these particles will look like a dense pool of molecules. And ...
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Is mass relative? [duplicate]

Since time is relative to the observer's velocity, does that mean that velocities are also relative, since the same distance is covered in a different time, depending on your reference frame? If ...
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How to calculate the speeds two objects need to move at in order to reach different destinations at the same time [closed]

For example: On a graph there are two points. Each point has a different destination. The distance between Point A and its destination is 50, and the distance between Point B is 100. The points will ...
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Velocity while falling from table

Suppose there is a chain of mass $m$ in a semicircular tube of radius $r$. If it's pushed, then find the velocity of the chain while leaving the tube. This is a simple problem which we can do using ...
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How does acceleration relate to the rate of change of speed?

I am given the following question: The trajectory of a charged particle moving in a magnetic field is given by $\textbf{r}=b\cos(\beta t)\textbf{i}+b\sin(\beta t)\textbf{j}+ct\textbf{k}$ where $b,\...
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Maximum Rotation Speed

I looked at a question, elsewhere on this site, relating to the maximum 'theoretical' speed of rotation. The explanation using the speed on a black hole event horizon seemed reasonable to this person. ...
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Variables in rectilinear motion

I wrote a post few days earlier on circular motion but it seems i still haven't got the hang of it yet. When is this equation actually true? $s=ut+\frac{1}{2}at^2$ Suppose velocity is given by $v=t-2$ ...
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