Scalar quantity which is the magnitude of velocity.

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How fast do electrons move through a conductor?

If I apply $1 \text{ V}$ across a $1 \text{ }\Omega$ resistance, I'd get $1 \text{ A}$ flowing. $1 \text{ A}$ is defined as $1 \frac{\text{C}}{\text{s}}$, and $1 \text{ C}$ is equivalent to ...
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6answers
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How fast is Earth moving through the universe?

As the galaxy is moving and the solar system orbiting the galaxy and the Earth orbiting the sun. So how fast is each object moving and what is the fastest we move at? Do we even know how fast the ...
5
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2answers
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How to compute the speed of sound in relativistic hydrodynamic?

In Weinberg: Gravitation and Cosmology chapter 2.10 (Relativistic Hydrodynamics) the speed of sound is derived as $v_s^2 = \left(\frac{\partial p}{\partial \rho}\right)$ and the equation of state ...
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5answers
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2 balls falling hit the ground at the same time

There are 2 balls in a vacuum, next to each other but not touch. They are on the edge of a surface they will both leave the table at exactly the same time. One gets pushed harder than the other. The ...
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3answers
307 views

Calculating absolute speed of a relative object [closed]

Say you pick a point on the Earth. The earth spins at some constant $x (I don't know how fast, sorry). Now, that point has a different relative speed to a fixed point on Earth's orbit as it revolves ...
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2answers
233 views

Application of mean of speed distribution

Preface The definition of average speed of an object is defined by the distance travelled over time: $$v_{avg} = \frac{x_2 - x_1}{t_2 - t1}$$ The interpretation of speed is that when you multiply ...
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4answers
6k views

Is a signal traveling through fiber faster than a signal traveling through copper?

Does the transmission medium affect the speed of a signal? For instance does light traveling through a fiber cable get a bit from A => B faster than copper can transmit a bit the over the same ...
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8answers
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Accelerating particles to speeds infinitesimally close to the speed of light?

I'm in a freshmen level physics class now, so I don't know much, but something I heard today intrigued me. My TA was talking about how at the research facility he worked at, they were able to ...
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1answer
222 views

What's the highest speed one can obtain safely at home? [closed]

Among common household appliances, things one can make from stuff in the garage or hardware store, and reasonably safe, e.g. within reach of hobbyists and high school kids entering a science fair, ...
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16answers
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Why does kinetic energy increase quadratically, not linearly, with speed?

As Wikipedia says: [...] the kinetic energy of a non-rotating object of mass $m$ traveling at a speed $v$ is $mv^2/2$. Why does this not increase linearly with speed? Why does it take so much ...
7
votes
6answers
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How to calculate average speed [closed]

I recently encountered a puzzle where a person drove 120 miles at 40mph, then drove back the same 120 miles at 60mph. The average of the speeds is (40mph+60mph)/2 = 50mph, so the total trip time ...