Questions tagged [velocity]
The time rate of change of the position of an object
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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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1answer
15 views
Acceleration Problem [on hold]
I am doing kinematics in grade 11 physics and I've come across this really tricky question. Since there is no mention of time anywhere (and it asks for ... vs time graphs, I have no idea where to ...
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Confused with formula used for graph [on hold]
Can anyone explain to me how you get both the distance and velocity to zero using the following formula? I keep getting a different answer than that of the graph below. By the way, the object is ...
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A material point of mass m slides on a curve [on hold]
Can someone help me solve this question, please?
In the Oxy plane, where the axis Oy is vertical and oriented upwards, a material point of mass m slides on the curve xy = 1, 1/2 ≤ x ≤ 2, under the ...
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How to solve Linear motion problem? [closed]
At point K a particle which is at rest starts motion when $t=0$ it moves with a uniform acceleration $f_1$ for a period of $t_1$. Then it decelerates by $f_2$ for a period of $t_2$. Then it ...
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1answer
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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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Calculate the acceleration of a drone [closed]
It is for my final year project as a Computer Science student. I am building a desktop app drone simulator and I need some help with the Physics part of it. The scenario is as follows:
I have a drone,...
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5answers
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Why is escape velocity necessary if a rocket can just move up slowly? [duplicate]
I have read multiple explanations of escape velocity, including that on Wikipedia, and I don't understand it.
If I launch a rocket from the surface of the Earth towards the sun with just enough force ...
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1answer
28 views
Rotating sphere and the velocity of particle at the surface
If a sphere is rotating with speed $\omega$ and has a radius $r$, then after one complete revolution what would be the velocity of a particle at the surface (neither at topmost or point of contact of ...
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2answers
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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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2answers
120 views
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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1answer
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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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1answer
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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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0answers
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Speed of spherical projectile after x meters, considering air drag
I'm trying to write a bb gun calculator on my site, but unfortunately I'm not good at physics. This is the scenario:
If we have a projectile with a mass of 0.5 grams, leaving the barrel at 400 ...
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6answers
394 views
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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2answers
34 views
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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Violation of Einstein's speed of light postulate? [duplicate]
Consider the following scenario. You are moving towards the left with velocity c (Speed of light) and your friend is moving to the right with velocity c as well. Now the relative velocity of your ...
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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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0answers
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Bernoulli and the Venturi effect vs pressure
I am having a hard time understanding how pressure changes as related to flow, and also as it relates to the ideal gas law, assuming ideal conditions.
According to Bernoulli's equation, as pressure ...
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2answers
37 views
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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3answers
99 views
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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1answer
26 views
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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1answer
23 views
“Regularization” of the stationnary solution for diffusion in spherical coordinates
In spherical coordinates $(r,\theta,\phi)$, the stationnary diffusion equation is a Laplace equation $\Delta f =0$. The solution in a radial symmetry : $f=f_{\infty}-r_0/r$ where $f_{\infty}$ and $r_0$...
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1answer
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Can I find out magnitude and direction (+starting point) of a vectror using only one method? (graphical or mathematical)
Let's say I need to find out the magnitude and direction (by the direction i mean "position of a vector"/"starting point + direction") in uniform circular motion.
When I draw it into a diagram and ...
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2answers
75 views
Centripetal Acceleration as a Cross Product
Is it fine to express the centripetal acceleration as a cross product?
a=v X w (where a is centripetal acceleration, v is magnitude of velocity, w is angular velocity)
And is it v X w or w X v?
...
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1answer
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How is four-velocity automatically normalized?
This is a page from Sean Carroll's Spacetime and Geometry.There is a line in this page which says that the four velocity is automatically normalized.This absolute normalization is a reflection of the ...
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1answer
30 views
How to Find Jerk from Discrete Velocity Data?
I have measured the velocity of an object at discrete intervals. I want to find the corresponding acceleration and jerk of the object. How do I do this with discrete values rather than continuous ...
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1answer
43 views
How fast would an object at cruising altitude (around 10,600 m) need to travel to stay on the opposite side of the Earth to the Moon? [closed]
I am trying to figure out how fast an object will have to travel (at a height around 10,600 m) to never be in the presence of the moon. Meaning the object will always be on the opposite side of the ...
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2answers
73 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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2answers
73 views
Problem in finding the velocity of a wave
In my textbook, the equation for a wave is described as :
$y = A \sin{\frac{2\pi}{\lambda}(vt-x)}$
Now in this equation $x$ is variable as well as $y$. So when we will differentiate the equation by ...
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1answer
40 views
Force exerted by a motor, velocity, and friction
Some motor make an object move on a surface very slowly. One can write at steady state : $F_{motor}-F_{friction}=0$. The friction is supposed to come from the surface so : $F_{motor}-\mu_s m g=0$ with ...
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1answer
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Graph for Vertical Velocity of an airplane
I'm a fresh Calculus $1$ student struggling to make this graph somehow, I've been studying Chapter $1$ from James Stewart's single variable Calculus early transcendentals. Excercise $1.1$ is easy up ...
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Is it possible that D-T graph could be linear , but V-T graph will be log?
So , I have plotted the V-T & D-T plots for solar sail using the parameters (Using euler's method for solving the ODE based on Solar sail, estimate force & Here's my program :- https://github....
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1answer
50 views
Another question about Four-velocity derivation
Consider,again (Question about derivation of four-velocity vector) the following:
For a massive particle with position $x^{\mu}(t) = (x^{0},x^{1},x^{2},x^{3}) \equiv (x^{0},\vec{x})$ we define the ...
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2answers
66 views
Naive question about the need to construct the 4-velocity
Special relativity was not born as a 4-covariant theory. Instead, Einstein derivated the kinematical quantities without spacetime,therefore without 4-vectors.
Consider then the following:
First ...
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1answer
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How can I go and also not go faster than light?
Suppose I am in a spaceship. In this spaceship there is also my friend. So my friend and my relative velocity is zero. So no matter how fast my ship goes my friend's velocity relative to me is zero($0$...
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1answer
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Average Velocity Question (isolation?)
So there is this question i've been having trouble with for the past hour. It involved a child going down a ramp on a sled at and angle theta with a total system of mass. accelerates down a hill of ...
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7answers
156 views
Relative velocity greater than speed of light
Is it possible a relative velocity between 2 objects to be greater than the speed of light?
I know that it is impossible to reach the speed of light considering us to be immobile but is this ...
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1answer
50 views
Is the velocity gradient of a homogeneous viscous fluid constant?
The formula for the viscosity of a fluid (or even a gas) is equal to
\begin{align*}
\frac{F}{A} =\mu\frac{du}{dz}
\end{align*}
where $F$ is the force applied to the top layer of the fluid, $A$ is the ...
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1answer
93 views
What does speed of an object relative to water mean?
A swimmer swims with the velocity 1.25 m/s "relative to water". He has to swim across the river which is 150 meters wide. If his direction of velocity is perpendicular to the stream, he is taken away ...
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1answer
92 views
Gamma factor in special relativity
I try to derive the Lorentz transformation of a Lorenzt transformation frame an inertial frame $O$ to the frame $O'$ of a moving particle at constant speed v. We have four vectors $\textbf{x}'=\Lambda ...
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3answers
115 views
Surviving a fall into a balloon-filled pit [closed]
My brothers and i have been debating this question for years. If an average person fell at terminal velocity into the center of a pit that is 1 mile deep x 1 mile in diameter, and the pit is filled ...
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0answers
42 views
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
59 views
How can one experimentally measure the velocity of water flowing through a pipe?
I am planning to investigate the effect of bend curvature of a pipe on velocity of water. For this, I will need to find the velocity of water through various pipe bends. Would placing an object in the ...
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1answer
56 views
How to know what the area under curve represents?
Is there a way to find out what the area under the curve represents? For eg. If i gave you a graph of $v$ with respect to $t$ would you be able to tell me what the area under the curve represents ...
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1answer
34 views
Should there be a significant differential in wind velocity indoors vs outdoors in relation to Earth's rotating atmosphere?
What is the behavior of a rotating Earth's atmosphere indoors? Should there be any differences experienced between the atmosphere spinning in lockstep with the Earth outdoors vs. closed-off indoors?
...
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3answers
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Rule of addition of velocities in water
Is the speed of light still the same for all inertial observers in water?
If not, what are the rules of addition of velocities in water according to special relativity?
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4answers
115 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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0answers
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PG-Metric dr/dt
at the moment, I investigate some time in learning General Relativity and there I saw the Painlevé-Gullstrand Metric which is given as
$ds^2 = -dT^2 + \left(dr+\sqrt{\frac{r_s}{r}} dT\right)^2 + r^2 ...
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0answers
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If two surfaces slip on each other then their velocities along the common normal are equal?
If two surfaces slip on each other then their velocities along the common normal are equal?
