Questions tagged [velocity]
The time rate of change of the position of an object
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Linear and angular speeds of a train
I am using Radar sensor in a train.
Sensor is in the front part of the train to detect object and avoid collision.
It needs vehicle motion data to calculate objects longitudional and lateral speeds....
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How to derive the law of velocity transformation using chain rule?
I know there is a straightforward way to derive the law of velocity transformation in Special Relativity by just dividing $dx$ on $dt$. But I am interested here to apply the chain rule and see how to ...
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There are two velocities on the sphere. How to sum them on the sphere?
As shown in the figure, there are two velocities on the sphere, one is the velocity along the meridian direction, the arc length is its size, the other is the velocity along the equatorial direction, ...
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What's meaning of velocity of electron? [closed]
How do we define velocity of microscopic particles at small scales. As for macroscopic particle we can scale the distance travelled by object. But this is not the case with electron.
Still, while ...
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Independence of position and velocity vector [duplicate]
Hi I am a mathematics student with an interest in Physics. In our Physics elective our prof. said if $\vec r$ denotes the position vector then the velocity vector $\vec v = \vec {\dot r} $ is ...
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Spring mass system
While solving some spring block questions one doubt came in my mind ..is it possible to calculate maximum velocity of a point between two springs of different force constant attached to a block of ...
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Hyperbolic motion with non-zero initial velocity
The equations of hyperbolic motion in a single spatial direction with initial velocity of zero are pretty easy to find given a bit of googling, such as in this answer. And while I'm too rusty at ...
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Calculating relative velocity in three dimensional space
Given two points $\mathcal{A}$ and $\mathcal{B}$ in $\mathbb{R^3}$ whose position and velocity vectors are, respectively:
$$\mathbf{r_A}=\begin{pmatrix}r_{A_{x}}\\r_{A_{y}}\\r_{A_{z}}\end{pmatrix}$$
$$...
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How to decelerate from velocity $v$ to stop time $t$ over distance $d$? [closed]
I'd be grateful for some help with this problem I am trying to solve.
Let's say that I have an object travelling at a velocity $v$. I want that object to come to a halt in time $t$ AND travel exactly ...
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Vertically move in a helicopter to go somewhere on Earth [duplicate]
Is it possible to go from point A to point B (which are on same latitude) by hovering above A and wait till the earth rotates to point B below and then come down vertically?
I believe there would be ...
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Confusion about average value of $v^2$
I know that expected value of velocity means $$\langle v\rangle=\frac{d\langle x\rangle}{dt}$$
and since I know how to calculate $\langle x\rangle$ namely $$\langle x\rangle=\int_{-\infty}^{\infty}x|\...
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Speed is different when differentiating a function and when not differentiating
I have the function, $S(t) = t^2$.
When Finding speed $= V = \frac{dS}{dt}$, we get $V = 2t$.
Now If, I don't differentiate it and simply put
$V = \frac{Distance(S)}{Time(t)} = \frac{t^2}{t}$
We ...
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Velocity addition formula derived from velocity boosts
I understand the derivation for the equation the velocity in a boosted frame by taking the boosts of the differentials such that: $v'^{\mu}= \frac{dx'^{\mu}}{dt'}
$ where $x^{\mu} = \Lambda^{\mu}_{\, \...
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Dynamically changing acceleration of object moving towards sun due to gravity
For a collection of sci-fi short stories set in the rather near future I need an approximation of the time it would take a space ship to travel from an Earth orbit to Ceres.
In a previous story of ...
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Why isn't acceleration always zero whenever velocity is zero, such as the moment a ball bounces off a wall? [duplicate]
The answer to this homework problem is $\left(\text{D}\right) :$
I understand why we rule out options $\left(\text{A}\right)$ and $\left(\text{B}\right)$ first. However, I don't get why $\left(\...
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What happens to $P = F × v$ for a car moving on a frictionless surface and in vacuum?
I'm considering a scenario in which a car with an engine capable of producing maximum power of 200 hp is moving on a frictionless surface and in vacuum. Since no work is lost due to friction or air ...
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How fast will air travel to fill a vacuum?
Suppose I have a sealed glass cylindrical vessel of radius r and length l that is evacuated. I smash one end.
How long will it take for air to (a) reach the end of the cylinder (b) fill the vacuum ...
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Find radius of curvature, given a velocity vector and acceleration magnitude? [closed]
The particle P moves along a space curve. At one instant it has velocity $v = (4i-2j-k)$ $m/s$. The magnitude of the acceleration is $8 m/s^2$. The angle between the acceleration and the velocity ...
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How fast would a spaceship have to go to reach Alpha Centauri within a person's lifetime?
Given the recent news about the discovery of an "Earthlike" planet orbiting Alpha Centauri (our nearest stellar neighbour) it got me wondering just how fast would spaceship have to travel to be able ...
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Signs in relative vector addition
So I know the formula for relative vector addition is
$$w = \frac{v-u}{1-\frac{uv}{c^2}}.$$
How do I chose when to use this formula or its inverse transformation for solving vector addition problems ...
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Applying Lorentz Transformation
Lorentz Velocity Transformation:
$$v_x = \frac{v_x' + u}{1+\frac{uv_x'}{c^2}}\tag1$$
$$v_x' = \frac{v_x - u}{1-\frac{uv_x}{c^2}}\tag2$$
The speed of spaceship and scoutship are given relative to ...
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Speed of sound in a liquid mixture
I need to compute the sound velocity of a mixture of different magmas and their gases.
Thanks to this site I already found the way to compute the sound velocity of the gas, but what about the liquid ...
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How does the mass distribution and center of gravity affect the speed of a lego car down a ramp? [closed]
we are doing a research involving motion of an object with a nonuniform mass distribution, and we have to explain how mass concentration, mass distribution, and center of gravity will affect a Lego ...
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Special Relativity - two beams of light in opposite direction
I just want to first say that I'm aware I am asking a question due to my own confusion and ignorance and not because of anything to do with special relativity. I hope that's alright.
What I'm ...
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In the equation for acceleration (with known $v$, $u$ and $s$) why velocity is squared and displacement is multiplied by 2? [closed]
In the following equation $$a = \frac{v^2 − u^2 } {2s} ,$$ where $v$ is the final velocity, $u$ is the initial velocity, and $s$ is displacement. Why is velocity squared and displacement multiplied by ...
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A basic question on Heisenberg uncertainty and experiment
I’m not a physicist or anything even close. But what I understand from the reason for the Heisenberg uncertainty is that the photon is changing the volecity/momentum when it hits the particle. ...
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Lining up fans in a row
Im new to this website, and not extremely educated in the world of physics. I have a very basic (mostly high school, some college) understanding of physics. That being said, I work for the fire ...
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The maximum velocity of an object in water [closed]
Suppose we have the mass and volume of an object, like a sphere, with density less than water. We grab it under the water and leave it, so it will fly up to the surface. What will be the maximum ...
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Doubts in understanding the instantaneous velocity [duplicate]
I was studying about the fundamentals in physics and I read a defination of average velocity. It was like that average velocity is a physical quantity which gives the measure of overall rapidity of a ...
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Which is more important for a force of the impact mass or velocity? [duplicate]
If a 2 times bigger mass collides with an object in which a 2 times smaller mass collides but with 2 times the speed which one will produce more force on the object?
The object is stationary before ...
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Calculating Inital Velocity required to stablize an orbit of a moon
I am currently attempting to create a little solar system simulation and I was curious if there's a decent way to calculate what a moon or planet's initial velocity would need to be to remain in orbit ...
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How do I determine the components of a cinematic jump, for vertical and horizontal velocity?
I have been tasked with determining the feasibility of The Rock's jump in the movie 'Skyscraper' I am using projectile motion equations to determine it, but have gotten stuck whilst calculating my ...
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Calculating Acceleration
I'm having problems calculating acceleration for the following variables. I would have thought it would be extremely straight forward, except I am getting two different answers and do not know which ...
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Pressure on the outer hull of aeroplane on theoretical emergency landing
I'm trying to figure out the proper way to calculate the pressure on the hull of aeroplane when landing on water.
Let's say the horizontal velocity of plane is $1000$ km/h and it starts free-falling ...
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Is there any physical scalar potential where $U$ is also depends on $\dot q_i$s?
In the book of Classical Mechanics by Goldstein, at page 21, while deriving the Lagrange's equation, when the external forces are derivable from a scalar potential $U$, the author implicitly assumes ...
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How and why does momentum get transferred? [closed]
Let us imagine an isolated system and there are two objects of whatever masses and size. Let one object move towards the other object with constant velocity. We know, that when they collide, the ...
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Can an object have constant speed and tangential acceleration without undergoing circular motion?
Is it possible for an object to be moving with constant speed and a constant magnitude of acceleration tangent to this velocity but NOT move in a circular path? If there are other situations could I ...
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Can a bullet leave a gun and tumble to the ground?
This question seems to have been asked a few times in different configurations, but none of them answer my variation. I've struggled to understand this for nearly 15 years and had conflicting answers ...
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If kinetic energy is mass times the integral of velocity, isn't it just a product of mass times distance? [closed]
I'm still learning Calculus at the moment and I'm currently on integration. The moment I realized the "$1/2$" and square value in $v^2$ are just products of integration, can't one just use ...
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What does expressing ‘velocity’ as a function of $(x,y)$ mean? [closed]
This is a question from my textbook. We have been given an equation of trajectory (equation of an ellipse), and the question wants me to express the velocity vectorially as a function of (x,y).
I ...
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Can you jump higher if you run? If so, why? (High jumping)
I have often wondered why high jumpers can jump higher if you run. The way I see it is that you only build up horizontal speed, and since you're running on a plane, I cannot see how this speed can be ...
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Fastest hyperloop-like vehicle which a human could endure [closed]
I'm currently writing on a science-fiction novel where a transportation system like the hyperloop has been built.
Now, I'm wondering how fast I can make this. Since the plot takes place on many ...
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Help understanding why can't we measure absolute velocity?
(This is probably a clone of some other question, but I haven't been able to find a satisfactory answer, so I hope this is okay.)
So, I know that in special relativity, there's no such thing as a ...
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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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Predicting the tension in the rod of a pendulum
I'm trying to predict the tension in a pendulum with radius/length $r=0.4m$, mass of $m=0.1kg$, and dropped from an angle $\theta=15^\circ$. Also, I'm trying to find the tension at the lowest point of ...
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Relativistic velocity addition from time dilation
I'm trying to derive the relativistic velocity addition equation using the time dilation equations but I get a wrong result.
Assume the widely used scenario in which there are 3 clocks: O, A and B.
A ...
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How does one calculate the energy used depending on the velocity and air resistance of an object [closed]
I'm in need of a equation that can tell me how much energy/work I need to move an object inside a low air-pressure tube. The equation should (if possible) include drag, object velocity and mass.
If ...
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Possible paradox relating to acceleration, velocity, and work
I recently encountered a question that made me think of this "paradox":
Imagine the following situation:
There are two forces: Force 1 and Force 2. They accelerate a mass $m$ from the same initial ...
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Instantaneous velocity applications
I refered these two questions
Instantaneous velocity
How to interpret instantaneous velocity using limit?
and I understood how instantaneous velocity is defined. But why do we define it?
Velocity ...
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Sign of Velocity for a Falling Object
I'm working on a homework problem in Mathematica. We have to graph the height and the velocity of a function given an initial height and initial velocity. However, when I do the graph for the velocity ...