Scalar quantity which is the magnitude of velocity.

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2answers
189 views

At What Point Does Mass Cease to Matter?

I know very little about physics so I naturally have a lot of simple minded questions. Assuming I am piloting a rocket and want to obtain the fastest speed possible. At what point does mass more ...
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2answers
80 views

Speed and multiple images

Why an object (or something else) create multiple images of itself when it is moving fast? An earphone spinning in circle for example.
-2
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1answer
65 views

Objective velocity (Relativity theory) [closed]

Suppose that I have a velocity of (approximately) $c$. Then I decelerate with $c$ per hour for exactly one hour. Then I would know that I would be standing still in the end, because the decelleration ...
1
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1answer
85 views

Why does the wavelength gets shorter in the denser medium in refraction? [duplicate]

In the refraction, the wavelength gets shorter if it enters denser medium. Why is that happening? Is it just a phenomenon?
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1answer
53 views

Difference between escape velocity and speed [duplicate]

What is the difference between escape velocity and escape speed , is their any error if we use them interchangeably?
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1answer
91 views

Question about acceleration & deceleration in real world?

have searched the net and am not satisfied with any answer I have found to calculate the following:- Here is an example just for reference. Suppose I can accelerate my car from 0-100km/h in 10s. That ...
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1answer
49 views

Speed Calculater [closed]

I want to make an android calculator which can calculate speed of a vehicle by using mobile sensors(accelerometer or GPS) i am interested to calculate it by using accelerometer instead of GPS is it ...
1
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2answers
75 views

Calculating speed of satellite in vacuum?

Satellite speed is $35\ \mathrm{km/s}$ after burn for $500\ \mathrm{ sec}$ and after some days or months this speed is reduced automatically $34$, $33$, $32$ respectively. Questions: How the ...
23
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9answers
18k views

Can a human size object move so fast that it ceases to be observable?

In many anime, comics, movies, etc, we see a lot of super human beings moving and fighting at such high speeds that a regular human being cannot see that they are fighting or moving pass by. In ...
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3answers
187 views

Can rotating disk clocked at its center at the speed of light have an outer edge that travels faster than the speed of light? [duplicate]

I have been running this through my head for a few days and I understand I am probably missing something very simple here. If a wheel is spinning the outer edge will travel at a speed that is greater ...
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1answer
46 views

Behaviour of gases in a vacuum

I have a doubt related to the behaviour of gases in a vacuum. In the following figure: The grey part is the vacuum and the green part is the gas, let the gas be Carbon Monoxide. The following are ...
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2answers
38 views

light speed broadcasts [closed]

I’m a writer. I'm working on a story. It’s sold actually, but they want some changes and I’m trying to figure out the science.. IDEA: A distant planet picks up broadcasts from Earth, so the ...
0
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3answers
93 views

How do radar speed signs work?

Everyday when I'm going back home from college, I pass by this big radar speed sign and I've noticed that it does a peculiar thing. The sign is placed on a downward slope of the street. So say I'm ...
1
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0answers
26 views

Escape speed or Escape Velocity? [duplicate]

Which one should be the correct term escape speed or escape velocity? In one book it is given Speed whereas in another its velocity.
1
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0answers
75 views

Electric skateboard speed calculations [closed]

I have a slight issue figuring out how the mass of person (≈110kg) will affect the theoretical top speed achieved. Below are the details: (1) Motor kv : 270 kV (2) Batteries: 19.8V Motor Speed: ...
0
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2answers
140 views

What happens if a motorcycle going at 50mph crashes head into a car going at 60mph? [closed]

I wonder if a motorcycle (going at 50mph) crashes into a car (going 60mph), what is the damage that motorcycle will experience? Here's a diagram that shows what I've in mind: ...
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4answers
428 views

Speed as the fifth dimension

In spacetime there are four general dimensions, three of space and one of time. Why is it that other dimensioned qualities seem to be rarely considered as part of spacetime? For example, why isn't ...
1
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1answer
126 views

How fast would you have to run to create a mirror image?

So I was watching The Flash and in the most recent episode he runs so fast that he is able to create a mirror image of himself so that it looks like there is more of him than there actually is. So I ...
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3answers
55 views

What prevents me to accelerate an object to near light speed in space?

As far my limited knowledge go, things in space aren't slow down unless something interferes with them, so what prevents me to build a spaceship powered by nuclear power that will keep accelerating ...
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3answers
72 views

Initial speed in homework problem [closed]

This is a homework question. I tried to solve it, but failed. I had to translate this question, so please forgive me if it is poorly worded. In this question you can ignore the atmospheric ...
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1answer
64 views

How can we see the alien, who are travelling in light speed? [closed]

If aliens has the technology to travel in speed of light ,How can we see them with our 'below the speed of light' technology?. Because when we see that(!),definitely it will not be in its place.Is ...
4
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3answers
2k views

Why does the speed of the propellant limit the speed of a space ship in open space?

Isn't speed a relative thing in space? If so, why would the speed of a propellant matter? Why can't a space ship accelerate infinitely?
2
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0answers
39 views

Speed of breaking (guitar) string

As I was playing the guitar yesterday, one of the strings broke and injured one of my fingers lightly. Astonished by the power of a breaking string, I was wondering whether there is a way to ...
0
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1answer
40 views

What happens to centripetal acceleration if you change speed while rounding a corner? [closed]

What happens to centripetal acceleration if you change speed while rounding a corner?
17
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7answers
6k views

Why does the speed of light $c$ have the value it does? [duplicate]

Why does light have the speed it does? why is it not considerably faster or slower than it is? I can't imagine science, being what it is, not pursuing a rational scientific explanation for the speed ...
0
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2answers
86 views

Why is kinetic energy calculated using speed?

Why is kinetic energy calculated using speed? Since speed is distanced covered, and if a car moves 100 meters around a circular track -- stoping after moving half of the distance of the track -- the ...
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1answer
3k views

Gentle slope vs steep slope

Take for example a slide of 3m tall. Would an object (starting from rest) sliding down a gentle slope have a lower speed than a steep slope? (Note: Height of slide is the same,disregard friction.) ...
2
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2answers
415 views

Slowing down high energy neutrinos?

Which atoms can slow down high energy neutrinos? I mean in which medium high energy neutrinos will tend to slow?
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1answer
51 views

Speed limit to air travel? [closed]

Is there a hard limit on the speed of air travel on earth? That is, if you consider the way the human body reacts to gravity. Is there active research ongoing in this area?
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1answer
389 views

Two objects at different heights, would they be traveling the same speed?

If I were to drop an object at a height of 15 feet, then another object of the same mass at 20 feet, would both objects be traveling at the same speed? What would be the speed of which they are ...
0
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1answer
51 views

Differences in speed of light calculations in glass

I wanted to determine the speed of light in glass by using both of the following formulas : $$v = \frac{1}{\sqrt{\mu \epsilon}} \simeq \frac{1}{\sqrt{\mu_0 \epsilon_r \epsilon_0}} \;\;\; \text{and} ...
0
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2answers
80 views

Can Maxwell's law of distribution of velocities be used to determine a value for absolute heat?

I'm currently reading about Maxwell's law of distribution of velocities, and the thought occurred to me that I could use this to calculate the maximum temperature that an atom could reach. My theory ...
2
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2answers
127 views

Speed of light in teflon

I was wondering why some websites are talking about the speed of light in teflon because it seems (tell me if I'm wrong) that it is an opaque material. Or are they talking about the light as an ...
16
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3answers
6k views

How does electricity propagate in a conductor?

On a systems level, I understand that as electrons are pushed into a wire, there is a net field and a net electron velocity. And I've read that the net electron drift is slow. But electricity ...
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0answers
90 views

How to calculate maximum wind speed in a funnel (Venturi Effect)?

It must be in an open area, so nothing forces the wind, just himself. Lets assume that the wind is blowing only one direction. I assume that at some point the speed will stop increasing and it will ...
2
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0answers
95 views

Finger snapping: Maximum fingertip speed and generated pressure change

The wikipedia page for finger-snapping (or finger-clicking) describes the physics thus: There are three components to the snapping finger sound: (1) The "friction" or "sliding" sound between the ...
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0answers
62 views

Friction related question [closed]

A uniform chain of mass $M$ and length $L$ is hanging from the table. The chain is in limiting equilibrium when length $l$ of chain overhangs. It is slightly disturbed from this position. Find the ...
3
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1answer
58 views

How does a body accelerate that is put into a flow field with constant speed?

Imagine an infinitely long flow channel filled with water flowing at a constant speed everywhere parallel to the infinitely long dimension of this channel. Furthermore, imagine we place a body (say a ...
0
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2answers
76 views

Does the spring effect a moving ball? [closed]

There is a ball attached to spring which is streched out. The ball is held by a machine on the ground so it does not move, but when it is released it will quickly contract. At the same time a ...
3
votes
2answers
7k views

Calculate speed from accelerometer

I am trying to use my accelerometer on my mobile device (smart watch to be specific) to calculate a persons arm swing speed. The data returned from the accelerometer is in $m/s^2$. Since the ...
0
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1answer
81 views

Calculate constant acceleration for a length of track with start at rest and final velocity known [closed]

My maths and physics are rusty... I'm a bit ashamed, but I have this problem: Let's have a 1000m linear accelerator (mass driver) propel a payload at constant acceleration, with a final velocity of ...
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votes
3answers
249 views

Does Size affect Distance covered at constant speed? [closed]

How does size of an object affects its speed? Suppose if two objects of different sizes (very different indeed) moves at speed of say 100 mph for an hour, will the object greater in size covers the ...
2
votes
3answers
978 views

How to figure out the height it would take for an object to reach terminal velocity?

I'm trying to figure out how high an object would have to be dropped to reach it's terminal velocity. Specifically if an object had a terminal velocity of 520 mph, how would I figure out how high it ...
0
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3answers
156 views

How to tell if area is displacement or distance?

why is it not called "velocity v. time"? how do you know? If the y-value can be either positive or negative, the direction is then indicated. i think this is why it should be called velocity but ...
3
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1answer
73 views

Mechanical waves with slower speed than sound

Sound is mechanical waves of high and low air pressure transmitting with 300m/s. Are there high and low air pressure waves transmitting with lower speeds? How are they produced?
23
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5answers
4k views

Why is there a controversy on whether mass increases with speed?

Some people say that mass increases with speed, some people say that the mass of an object is independent of its speed. I understand how some (though not many) things in physics are a matter of ...
0
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2answers
47 views

Packets of information in the real world

Please excuse this apparently naive question. no one appears to have the answer. If a standard packet of data is travelling down a standard fibre, what is the physical time taken between the first ...
0
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2answers
62 views

Why can't we increase the speed of sound in a constant Temperature-pressure condition?

We know the speed depends on the kinetic energy. Imagine that we have 3 iron balls equally spaced and kept in space (zero gravity condition). If i push the first ball slowly it would travel slowly ...
0
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1answer
177 views

Change of direction in physics when an object in motion stops

Consider an object moving with an acceleration $a = -1 \text{m/s}^2$ starting with speed $v(0) = 4 \text{m/s}$ towards east and stopped after 4 seconds. (There are no friction.) After 4 seconds, the ...
5
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3answers
7k views

Does friction decrease as objects move faster against each other?

I was told that the faster two objects move against each other, the less the friction between them would be… compared to if they were moving slower. So does friction decrease when the body is moving ...