Scalar quantity which is the magnitude of velocity.

learn more… | top users | synonyms

2
votes
2answers
349 views

What does it mean to be stationary?

I'm looking for a simple answer. What do we regard a stationary. Do we mean an object that is not moving noticeable from the viewers perspective because then a parked car would be considered ...
4
votes
1answer
1k views

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 ...
5
votes
2answers
236 views

Is there a limit to frames per second to be captured?

Today we see ~100,000 fps cameras for hyper slo-mo. Is there a physical limit for frames per second for a camera? Speed of light maybe? How?
1
vote
3answers
5k views

Is the same amount of electricity used for ceiling and table fans on different speeds?

We use ceiling and table fans in home which are can be set to low or high speeds using regulators. I want to ask that does it uses or consumes same amount of electricity at different speeds? Here, ...
7
votes
6answers
83k views

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 ...
-2
votes
1answer
104 views

How Was the Speed of Light Discovered? [closed]

The title pretty much says everything; I just want to know how the speed of light was discovered.
-2
votes
1answer
176 views

How to calculate the dependency of speed and weight of a servo? [closed]

Here is a digital servo: Servo By using the information of details of that thing what is the way to calculate the dependency of the speed of the movement of the car if the load upon the servo is N kg ...
2
votes
1answer
104 views

Speeds and frames of reference

When reports state that Voyager is traveling at ~17kmps or that a comet is traveling at 600kmps, what are these numbers relative to? Given that the Earth travels at ~30kmps and orbits the Sun which is ...
0
votes
1answer
61 views

Speed Distribution [closed]

I came across a problem which reads: The speed distribution function of a group of N particles is given by: $dN_v = kv\; dv\; (V>v>0)$ $dN_v = 0 \; (v>V) $ (a) Draw ...
1
vote
1answer
49 views

Does speed of writing data on an optical disk affect the speed of reading data? [closed]

Does speed of writing data on an optical disk ( like DVD ) affect the speed of reading data from that disk ? even a little?
11
votes
2answers
814 views

Is it possible to travel at precisely the speed of sound?

I've been talking to a friend, and he said that it's impossible to travel at exactly the same speed as the speed of sound is. He argued that it's only possible to break through the sound barrier using ...
-2
votes
1answer
451 views

Average speed question [closed]

Find your average speed if you go 15m/s for 1000 m and then 30m/s for 1000 m I understand that average speed is total distance / total time. The distance for this problem would be 2000m travelled. ...
-2
votes
1answer
156 views

Calculation of 12000 Lunar Orbits/Earth Day [closed]

I am really interested in the calculation of the following speed value in meter-per-second unit: Speed of something that is able to travel in one earth day the distance that it would take for the ...
0
votes
1answer
723 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
votes
3answers
5k views

Why does an object with higher speed gain more (relativistic) mass? [duplicate]

Today, in my high school physics class, we had an introductory class on electromagnetism. My teacher explained at some point that an object with a very high speed (he said it started to get somewhat ...
2
votes
2answers
216 views

How much more energy would I spend if my bicycle was 2 kilos heavier? [closed]

I have a bicycle weighing 8 kilos. An 10 kilometer ride averaging 20 km/h requires z kWh's of energy. How much more energy would I spend if I added 2 kilos to my ...
1
vote
0answers
76 views

Could Elon Musk's proposed Hyperloop transportation system reach 760 mph? [closed]

Hyperloop is a proposed mode of High speed transportation by Elon Musk. Theoretically it's speed is about 760 mph. Can 760 mph speed be achieved with this project ? Hyperloop - Alpha - ...
-1
votes
4answers
1k views

How does a train, airplane measure its speed?

I always get the doubt about this. I know that a bike measures its speed based on the motion of its front wheel. So what is the case with train? Is it same principle? Then what about an airplane? Is ...
0
votes
1answer
132 views

How much speed is maintained in a 90 degree turn? [closed]

How much speed is maintained in a 90 degree turn? Is there an equation for this? I was recently driving and took a 90 degree turn while coasting at 25 mph and it did not seem like I lost very much ...
9
votes
3answers
3k views

What is the speed of time

When we measure the speed of a moving element we do it with the help of a reference frame. Now if we need to measure the speed of time, is it possible? Is time really has speed? Thanks in advance.
2
votes
1answer
200 views

Steel rod to Mars vs the speed of sound, how is supersonic travel possible?

I remember reading this passage in the "Feynman Lectures", where Dr. Feynman describes an experiment in which a theoretical metal rod of length equal to the distance between Mars and Earth is arranged ...
-2
votes
3answers
136 views

Is it possible to defy time using speed? [closed]

I have always wondered if we were to travel at past the speed of light (even beyond the current capability) would we be able to slow down time around us? I have asked my teacher at school and he has ...
0
votes
3answers
360 views

Velocity is “Distance/Time” in a particular direction OR simply “Displacement/Time”?

Is velocity: Distance/Time in a particular direction, or simply Displacement/Time? Or both 1 and 2 is the same thing?
1
vote
2answers
198 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?
-1
votes
2answers
50 views

Paraphrasing speed and heat capacity [closed]

Can we call speed the change in distance per time? Further, would you phrase heat capacity as change in heat per temperature or change in temperature per heat? The reason for this question is that ...
-1
votes
1answer
109 views

Temperature loss of a moving object

I would like to know how to calculate the temperature change of a moving object. For example if I throw a ball that is warmer than the surrounding air, how much would it lose form it's temperature in ...
-2
votes
1answer
77 views

A question about speed [closed]

A object with mass 0.5 kg slides in straight line for 200 m, where the friction act on it is 0.4 times the normal reaction acting on it. Find its initial speed. I let $u$ be the speed. ...
4
votes
6answers
5k views

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 ...
-2
votes
2answers
625 views

Electric potential energy and speed

If we have electric field and we put electron there , the electron will move in the opposite direction as the electric field. My question is electron in that direction will speed up or slows down ? ...
5
votes
2answers
1k views

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 ...
1
vote
1answer
142 views

B-field and Magnetic forces, speed of a particle

Let's say I have a particle moving perpendicular to a uniform magnetic field of magnitude $x \ T$, and it moves in circle with a fixed radius. How do I find the speed of this electron? Initially I ...
1
vote
1answer
73 views

Can a link between photons that don't exist at the same time provide communication with the past?

They have published something about a link between photons that don't exist at the same time. Does this means that it is possible to build a device that will receive messages from itself but these ...
-1
votes
1answer
65 views

What is the maximum speed of a change? [duplicate]

Is there any limit on the speed of changing something? For example a particle is transformed to some other particle; This takes some time or is absolutely instant? If every change takes some time, ...
0
votes
1answer
71 views

Is there any case where one would use, snap, crackle or pop? [duplicate]

As we all know, if you differentiate distance with reference to time, you get speed, and likewise, differentiating speed you get acceleration. However, if you keep differentiating, to the rate of ...
1
vote
1answer
88 views

Gyro vs Accelero : Why is that assessment false?

Can we say that the Accelerometer's values are somewhat the integral of the Gyroscope's values ? I think that because I know that the velocity is the derivative of the position with respect to time ...
2
votes
2answers
1k views

Does inertia increase with speed?

I have heard that when the speed of the object increase, the mass of the object also increase. (Why does an object with higher speed gain more (relativistic) mass?) So inertia which is related to ...
1
vote
2answers
117 views

Currents and the Speed of Light

Why is it that currents don't flow at the speed of light, but rather significant ratios of the speed of light. I don't have any formal reasoning as to why they would flow at the speed of light-I just ...
11
votes
2answers
3k 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 ...
2
votes
1answer
2k views

Which derivation of drift velocity is correct?

In the derivation of drift velocity I have seen two variations and want to know which one's correct. $s=ut+\frac{at^2}{2}$ Assume that the drift velocity of any electron in any conductor is : ...
2
votes
1answer
296 views

How to find speed when accelerating down a slanted wire

I saw this picture on one of my social media sites with the caption, "I'd do this in a heart beat! Who's with me!" I was about to go balls to the walls and say, "I'm in! When and where??" But then ...
-2
votes
1answer
179 views

How to smooth a path (and speed calculation) based on randomly timed coordinates? [closed]

first my actual problem. then my try on improving the current way of solving this with the wish for feedback or even a solution :) gpx file with lat/long, elevation and time. wanna calculate speed... ...
-1
votes
1answer
239 views

Acceleration, velocity and speed

It is given that acceleration is constant, so can we infer that average speed and velocity are the same?? Moreover, circular motion is out of the question, as the function of x(t) where ...
2
votes
3answers
666 views

Wind effect on driving a ground-based vehicle

A friend of mine seems to think that wind affects the ground-speed of a ground-based vehicle in the same way airspeed affects an airborne aircraft. i.e. If faced with a 10mph headwind, your car isn't ...
0
votes
1answer
2k views

Speed of a fly inside a car

A couple of weeks ago I was travelling in a car (120 km/h approximately) and I saw a fly flying in front of me (inside the car, near my nose, windows closed). I wonder how was that possible. Does it ...
4
votes
2answers
1k views

Help me get out of a speeding ticket

I was driving uphill from a complete stop for a distance of .4 miles estimated to take 1 minute in a navigation app. I was pulled over right after cresting the hill. The cop had me on radar going ...
4
votes
3answers
173 views

If an electric car were to drive without having to stop, would the range be greatly affected by the speed at which the vehicle is moving?

Of course aerodynamics factors into this question, and the faster you are moving the more air you have to push out of your way, the more energy you use. But would the difference be only a small ...
13
votes
8answers
5k views

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 ...
-4
votes
3answers
352 views

Speed of an object in air versus in vacuum

Okay, imagine that you are shooting a rocket down a tunnel that is 60 miles long and the rocket is travelling at 60mph, so the rocket should reach the end of the tunnel in a hour, right? Yep, in an ...
1
vote
1answer
121 views

Weightlessness on Earth

Would the following work? Imagine one would 1) create a straight 4000 km long tube (at ground level), following the curvature of the Earth, wide enough to hold a pod the size of an aircraft cabin; ...
-2
votes
2answers
15k views

How exactly does mass affect speed?

I konw that mass affects weight (force), so how does that relate to speed? F=ma. so how does all this affect speed?