Questions tagged [speed]
Scalar quantity which is the magnitude of velocity.
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How fast does an electron move?
I've been reading this website: www.physics.wayne.edu/~apetrov/PHY2140/Lecture8.pdf to learn how fast an electron moves in a circuit.
On page #8, #9 and #10 It says to take the Cross-sectional Area ...
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Speed between two cars with radar
I found a programming problem that calculated the speed between two cars as below and I would like to know how the calculation is done. It is about determining the speed of lead car. The coordinate ...
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3answers
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How to calculate car engine acceleration and deceleration?
I'm trying to program some kind of car game in unity just for practice. So I want to start off with an engine that behaves normally, so I can then convert the engine's RPM into torque.
Currently, I ...
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Speed of Transverse wave and frequency in sitar wire [closed]
I have a problem to solve though i am not clear on concept.
I know, $V = C (T/m)^{1/2}$
Where $C$ is constant, $T$ is tension , $m$ is mass per unit length.
Here is the problem
A sitar wire in ...
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How to increasing the swing frequency/speed of pendulum with hollow sphere enclosing small solid sphere?
When a small solid sphere is enclosed inside a hollow sphere, for a pendulum. How it will change the swinging nature of the pendulum? How can we increase the swinging frequency/speed of the pendulum?
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High speed and low speed photons (hypothesis - difference/relation)
In this question I found an interesting answer with the source.
Quotation:
A telescope viewing a supernova from over 16 billion light years away
recently clocked the low energy photon arriving 5-...
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2answers
53 views
What is the exact mechanism of flow of electricity?
When a steady current
flows through a conductor, the electrons in it move with a certain average ‘drift speed’.
One can calculate this drift speed of electrons for a typical copper wire carrying a
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4answers
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What is the difference between uniform velocity and constant velocity? [closed]
I think that uniform velocity implies constant speed but not constant direction. while constant velocity implies constant speed without any changes in direction.
Both tell us that there's no ...
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1answer
25 views
Avarage Speed conventional formula VS Mean Value of Multiple Speeds [closed]
Here the basic problem:
The motion of an extraordinarily jubilant bird flying straight up and down is given by the graph below, which shows the vertical position y as a function of time t.
What was ...
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3answers
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Why Didn't the Energy-Momentum Relation Work?
I am currently studying for the GRE Physics subject test by working through published past tests. My question is about problem 20 from the test GR8677:
A positive kaon ($K^{{}+{}}$) has a rest ...
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2answers
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How can speed at a given position be estimated from a bunch of average speed measures at different positions?
I have loose measures of average speed in different positions (speed is in the x axis given particularities of my own problem)
How can I estimate a fitting curve for 'instantaneous speed at each ...
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1answer
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Is it true that if one stood on Westminster Bridge with a radio, one would hear the chimes of Big Ben via the radio sooner than in the real world?
I was reading this review of Damon Krukowski’s Ways of Hearing in The Spectator when I stumbled across this claim:
“And before the renovation of Big Ben began, if you stood on Westminster Bridge ...
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45 views
How can the velocity of electrons in graphene be measured?
I'm trying to understand how one can measure the velocity of electrons in graphene, from an experimental point of view.
Does anyone have some clue?
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9answers
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The instant an accelerating object has zero speed, is it speeding up, slowing down, or neither?
This problem is from Khan Academy. Specifically for the blue point circled in red, the answer is that at this blue point, the object is neither speeding up nor slowing down. When I think about the ...
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1answer
28 views
Force measurement [closed]
We have a bike and a biker on it of mass 81 kg combined. Biker can reach speed around 30k/h.
And the question is: how to measure the force (in Newtons) applied on the bike to reach that speed in 10 ...
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1answer
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Is there an intrinsic speed of time? [closed]
If time and speed is relative, then we could double the speed of every particle in the universe, as this increases the clocks rate we shouldnt be able to tell any difference.
But my question is, in ...
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True Airspeed from Indicated Airspeed, Temperature, and Altitude
I'm working on an aircraft problem to figure out the true heading we need to fly in order to end up where we want with the presence of wind, and I think I have the whole thing figured out except for ...
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1answer
36 views
Scale diagram confusion
I’m familiar with scale diagrams where three forces act upon an object and trigonometry is used to find the resultant force, but I’ve come across questions that use units of velocity instead of force. ...
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7answers
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Is there centripetal acceleration with velocity of 5 m/s?
So if an object is moving at $5\ \mathrm{m\ s^{-1}}$ in a circle, is it accelerating?
Me and a friend are having a conversation about this.
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How does different shuffleboard powder affect the disks' speed
I do know there is friction and surface tension involved here but am not sure on how exactly does different kinds of shuffleboard powder affect the disks' speed.
So taking into the account the ...
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2answers
43 views
Speed and tangential acceleration in pendulum motion
Speed is a scalar quantity which corresponds to the magnitude of velocity, so it must always be nonnegative.
In a general 2d motion, the tangential component of acceleration is given by the time ...
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1answer
27 views
Would not the oscillation of light slow down the wave? [duplicate]
Would not the oscillation of the light wave slow down the wave? Does light travel at "c" of its net position over time, or does it travel at "c" on the wave?
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1answer
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Meaning of REALLY Slow Speeds
So we have a fairly good grasp of how entities behave at extremely fast speeds (visa vi relativity etc) but what about incredibly slow speeds?
I’m a Physics student and we were covering Broglie waves....
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How is vectorial Doppler computed when both transmitter and receiver are moving?
In a technical document, I have found the following formula for the Doppler of two moving devices:
$d=\frac{\bar{r}_{rx}^T\cdot \bar{v}_{rx}+\bar{r}_{tx}^T\cdot \bar{v}_{tx}+2\cdot \alpha\cdot D}{\...
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1answer
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Does Horizontal Velocity remain constant when it hits a surface in a Parabolic Motion?
It is told in one of the answers that the horizontal velocity stays at 4.0 m/s after the ball bounces from the plate.
Why is it still at 4.0m/s, isn't there friction or is it neglected for the sake ...
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2answers
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If a black hole is created from light, can this black hole then move at the speed of light?
Imagine we managed to squeeze light into a very tiny region of space so that the energy concentration at that point becomes a black hole. Can this black hole then move at the speed of light?
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3answers
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What is the best way to conceptualise a 'division' [closed]
This may seem like a strange question, but my question is more along the lines of trying to figure out how people were able to 'discover' the formulas which have shaped our understanding of the ...
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0answers
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How to express the Earth's orbital speed as a function of time?
I would like to create a function that tells me the orbital speed of Earth at any given day. The vis-viva equation says that
v=√(GM(2/r-1/a) ), expressing speed as a function of distance from the ...
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3answers
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If you were to push a block in space in an ideal vacuum scenario with zero friction, what would be the final velocity of that object
Say you push an object with 10 N force(just once and let it go) of mass 10kg object in space with zero friction and nothing in the way of its path. What would be the velocity of that object?
I would ...
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1answer
55 views
Calculate speed of an object using angle and time [closed]
I haven't had any physics class or anything close to that in a long time, and I'm currently confronted with an exercise I don't remember the formula(s) to solve it.
Assuming I have an object of ...
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1answer
101 views
Is it speed or acceleration that leads to time dilation? [duplicate]
Is it acceleration or speed that leads to time dilation or both?
For example, when a spaceship accelerated to (almost) the speed of light, then reversed course to come back towards earth, does this ...
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1answer
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Can a projectile bullet kill? [closed]
Today, I was watching a movie, in which a person shot a gun in air. The bullet went high in sky, became stationary for a moment and dived back and killing a non-innocent person by hitting him in head ...
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0answers
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Spiral lamp chane state speed [closed]
Question is how fast halogen lamp reach it full temperature, going from cold (not light) state to full light emit state. how fast in milliseconds it takes,
imagine: if led lamp work instantly like 0 ...
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4answers
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Why does a car's steering wheel get lighter with increasing speed [closed]
I've noticed it is difficult to turn the wheels of a car when the car is stationary, especially cars without power steering, which is why the power steering was invented. However, I've noticed it ...
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2answers
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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 ...
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1answer
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Why $g$ on equator is less than $g$ on poles? [duplicate]
I found this on my physics book. The book says $g$ on equator 9.78 $m/s^2$ and on the poles 9.81 $m/s^2$. Is it due to gravity?
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2answers
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What is the difference between velocity and speed? [duplicate]
What is the difference between velocity and speed? could anyone describe it more specific? does velocity have direction?
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1answer
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Does the weight on a car's wheels decrease with increasing speeds? [duplicate]
Ignoring the reduction in fuel weight as it burns, does the weight on a car's wheels decrease with increasing speeds? If so, by how much and is there a fomula for calculating that? At what speeds ...
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1answer
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Two containers that have the same volume (let say 500 liter) but are different in shape
I remember from school, one time a teacher explain us the following:
two containers of the same volume, but one is thin and tall, and the second is short and wide.
then if we fill them with water from ...
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2answers
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Would a human age faster if these certain conditions are met?
So, a human would travel in a rocket in outer space. There is little to no gravity, and the pressure may or may not have an affect (?) on what i'm about to ask. It has been proven that when a human ...
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3answers
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Why is a particle non-relativistic when its kinetic energy is small compared to its rest energy?
For example, nucleons in nucleus are in motion with kinetic energies of 10 MeV. Their rest energies are about 1000 MeV. Kinetic energy of nucleons is small compared to rest energy. They are hence ...
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1answer
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Calculation of speed from accelerometer data
I am trying to use my accelerometer on my mobile device fitness band to find the speed of walking and running.
I conducted my experiment of walking and running on treadmill where I asked a person to ...
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3answers
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Effect on speed when decreasing the magnitude of acceleration
I'm struggling to come up with an answer to the following situation and question:
"Suppose you are driving your car along a straight road in the positive direction and are speeding up (increasing ...
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2answers
153 views
What would the position vs. time graph look like if the velocity vs. time graph was a curve?
In my physics class we are learning about velocity vs. time graphs and position vs. time graphs for an object. We have learned that if the object is moving with constant velocity (this would be a ...
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3answers
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How does the increase of heat increases the speed of a particle?
I am fairly new to the thermodynamics topic, I have been introduced that as the temperature of a particle increases, so does the speed of the particle; it moves faster. However, I never been told how ...
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Does multiple tensioning pulley affects the belt speed?
Consider a multiple pulley system with the main pulley(30mm) attached to the motor shaft and multiple tensioning pulley in different locations(all are 15mm), driven pulley of 15mm is connected to the ...
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Where does this equation come from?
I am investigating about viscosity of fluids and I found the following equation to calculate the viscosity:
$$\nu = \frac{2(\rho_s-\rho_l)\cdot g \cdot r^{2}}{9\cdot\Delta v} $$
The experiment ...
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1answer
113 views
Sound and gravity
How would heavier gravity (or lighter gravity) affect sound in terms of what I hear?
For example, say there is a planet that is capable of supporting human life, but it has heavier gravity than ...
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4answers
198 views
Why is escape velocity independent of direction of projection?
However, for any body projected with a velocity less then the escape velocity, the final maximum height will vary with variation in angle of projection. But why is this not the case in case of ...
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2answers
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Why is $\sqrt{gR}=v$ same for finding Minimum and Maximum Speed?
I was wondering this: Why is the $\sqrt{gR}=v$ the same for finding minimum speed and maximum speed? Like if you are wondering the min. velocity for keeping a rollercoaster on track when on top of the ...
