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Questions tagged [velocity]

The time rate of change of the position of an object

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When and how do we use the formula Power = force X velocity?

I'm unable to understand the solution given in this book mine... Why are we adding the resistive force? In fact, i would really appreciate if someone explains the question to me, I'm really struggling ...
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2answers
78 views

Are mass and velocity complementary

Are mass and velocity complementary? I would like to know if there is a Heisenberg uncertainty relationship between the two. [EDIT] No answers so I thought I would expand a little. The reason I ...
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0answers
80 views

Using the Kalman filter given acceleration to estimate position and velocity [closed]

I am reading data from an accelerometer. I want to use this data to estimate velocity and position. Originally, I performed a double integration of acceleration to read this data, and as confirmed by ...
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2answers
61 views

Deriving the boundary condition for this flow

The Question: Suppose a circular cylinder of radius $a$ moves with constant velocity $U$ in the $x$-direction in a two-dimensional irrotational, incompressible flow whose velocity decays to zero at ...
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1answer
108 views

What (conceptually) is “Four Velocity”?

Too many text books (in fact, all of them that I've found including 'Gravity'), just throw out the term Four Velocity without digging into what it means, exactly. I understand $\frac{dx}{dt}$, but I ...
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2answers
95 views

Kinematics problem invloving position and time [on hold]

An object is moving along X axis with position as a function of time given by $x = x(t)$. Point $O$ is at $x = 0$. The object is definitely moving towards $O$ when 1. $\mathrm dx/\mathrm dt < 0$ ...
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1answer
48 views

Calculation of polar velocity components given cartesian counterparts

I would like to calculate the polar velocity components given the position $(x,y)$ and velocity $(u_x,u_y)$ in Cartesian coordinates. First of all, $$ r=\sqrt{x^2+y^2}\text{ and }\theta=\tan^{-1}\left(...
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2answers
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How instantaneous speed is defined as magnitude of instant velocity? [closed]

Let $s=$distance (a variable) we define instantaneous speed = magnitude $\left[\frac{ds}{dt}\right]$. However instantaneous speed is also defined as magnitude of instantaneous velocity i.e. ...
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2answers
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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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1answer
33 views

Velocity question which involved forward difference and back difference

Suppose one person at $t_0$ is at the location $p_0$ at $t_1$ is at the location $p_1$ at $t_2$ is at the location $p_2$ Then question: this person velocity at $t_1$ is $(p_1-p_0)/(t_1-t_0)$ Or $(...
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1answer
43 views

Speed of Light and Relative Velocity [duplicate]

Yesterday I was going through the idea of Relative Velocity in which, when the bodies are moving in opposite directions, their velocities add up. So, if one of the bodies in consideration is light, ...
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2answers
130 views

Question about the physical meaning of normalization of 4-velocity

I'm struggling with a concept of normalization of 4-velocity in Special Relativity (and General Relativity eventually). Well, after a bunch of introduction to vector/tensor calculus we came up with ...
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2answers
137 views

Uniform motion with non-uniform velocity

Let's suppose that there is a body which is moving with non-uniform velocity in the straight line. In the first hour it travels with a velocity of 50 km per hour and in the second hour it stops for 30 ...
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2answers
50 views

How to calculate average velocity using a series of measurements? [duplicate]

Assuming there is a series of delta time and displacement measurements, there are two way to calculate the average velocity I can think of: Divide total displacement by total time. Average of all ...
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1answer
116 views

Question about acceleration and velocity [closed]

A canoe is drifting left toward a hungry hippo with a velocity of $7 m/s$. The canoe rider starts paddling frantically, causing the canoe to travel to the right with a constant acceleration of $6 m/s^...
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2answers
55 views

Can a falling body on earth exceed its terminal velocity in a huge vacuum container?

Im not so sure about why a body has a terminal velocity. According to my knowledge it is due to the air drag. Force created by a falling body as it accelerates downwards due to gravity when equals the ...
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2answers
60 views

1D Motion: Average Velocity without Direction?

How come this solution doesn't include direction for average velocity since it is a vector? Calculate the average velocity at a particular time interval of a particle if it is moves 5 m at 2 s and ...
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2answers
95 views

Looking for the Formula for Uncertainty for Velocity

In a lab I'm working on, we used a formula for uncertainty of area: $$\sqrt{\left(\frac{δl}{l}\right)^2+\left(\frac{δw}{w}\right)^2}$$ We are asked to now find uncertainty for velocity (m/s) and the ...
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2answers
34 views

Increasing speed of a car using more motors? [closed]

I am making a robot car with four wheels. Every wheel will be attached to a motor. If I use four motors and four wheels , will I get more speed then using two motors?(If all the motors rotate at same ...
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0answers
47 views

How to make a car go down a ramp at contest velocity even when the angle of the ramp is changed [closed]

This is a high school project, I need to make a car go down a ramp at a contest velocity even when the angle of the ramp is changed, I was hoping if anyone could help me, figure out some way of doing ...
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1answer
209 views

Calculate distance an accelerometer moved

I am reading accelerometer data and want to determine the distance that the accelerometer is moved. ( My question is similar to the one placed here, Calculate speed from accelerometer . I just feel as ...
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1answer
67 views

Pendulum hanging from moving wagon [closed]

My Question is: What is the equation describing the angle of the pendulum (theta) depending on the time depending position of the wagon(x(t)). theta( t, x(t) ) = ? Note: Neglecting any sort of ...
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0answers
107 views

What is the normalized Maxwell-Boltzmann velocity distribution for 2D lattices?

The Maxwell Boltzmann velocity distribution is most of times deduced in 3D on books. How does it looks like in 2D?
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1answer
161 views

What is the magnitude of acceleration given $v_i$, $v_f$, and $x$?

I'm really struggling with this question that is part of my physics assignment. Any help would be appreciated. This is the question: A speed skater moving to the left across frictionless ice at 8.4 ...
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0answers
69 views

Gravity and rotating torus

Questions: Would a spinning torus lose its weight? Would a solid torus, spinning at 7,81 km/s radial speed completely loose it's weight on Earth-like object? Would it 'fly away' at higher speeds? {...
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1answer
80 views

Speed, velocity, and momentum of light

As far as I understand speed is a rate of travel and velocity is a directional rate of travel. The equation for momentum is given as follows $$p=mv$$ Where $m$ is mass and $v$ is velocity. Case 1. ...
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1answer
21 views

projectiles-kinematics

Let's just say that I have two identical spheres at the same height. Both of them are given the same push (same velocity). One of the spheres is projected vertically upward and the other is projected ...
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7answers
4k views

What's the difference between average velocity and instantaneous velocity?

Suppose the distance $x$ varies with time as: $$x = 490t^2.$$ We have to calculate the velocity at $t = 10\ \mathrm s$. My question is that why can't we just put $t = 10$ in the equation $$x = 490t^2$...
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2answers
56 views

Propulsive Power, Thrust and Velocity

If my rocket requires thrust $T$ to maintain a velocity $v$, the propulsive power can be calculated using $$P=Tv$$ Assuming the same friction (so the required thrust to maintain the velocity doesn't ...
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1answer
54 views

Relation of velocity and angular momentum in quantum mechanics

in quantum mechanics (non-relativistic or relativistic), when the angular momentum of the particle change is the velocity effected? are we assume the angular momentum equal zero when we determinate ...
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1answer
29 views

calculating velocity of electrons in a vaccuum tube( read description)

If I use a high voltage DC current in a vacuum tube to bring a lower power AC current into a vacuum tube, how do I calculate the average velocity of the AC electrons?
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4answers
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What would qualify as a deceleration rather than an acceleration if speed is unchanged?

The instantaneous acceleration $\textbf{a}(t)$ of a particle is defined as the rate of change of its instantaneous velocity $\textbf{v}(t)$: $$\textbf{a}(t)=\frac{\mathrm{d}}{\mathrm{d}t}\textbf{v}(t)....
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1answer
37 views

Direction of Friction of a cup on a table cloth [duplicate]

I'm having a bit of trouble figuring out which direction kinetic friction is supposed to act in. A glass of water is placed on a cloth at distance d from the table edge, and the cloth is spread out ...
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1answer
61 views

Difference between gravity and wind in simulation [closed]

So this is more of a conceptual question for simulations. I have gravity in my simulation that is going to the side: $g=(0,10)$. I know that gravity is acceleration. But is wind acceleration (...
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1answer
34 views

How to find each point's height of a projectile? [closed]

Tom in $20$ m/s velocity he kicked a ball with $60^\circ$ angle with vertical line. $30$ meters away from the place Tom kicked the ball, there is a goal post whose height is $1.8$ meters. If there is ...
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1answer
40 views

Speed of light limitations [duplicate]

In any circular cyclotron, how can the proton projectiles approach each other at more than 50% of the speed of light without exceeding the speed of light relative to each other?
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1answer
35 views

Would particles in this container go over light speed? [duplicate]

Imagine a container which contains a speaker and gas at normal pressure inside. Now imagine it moving at almost light speed (maybe c-100m/s) if the speaker makes a sound, causing particles to move at ...
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1answer
63 views

Is the velocity of electrons in different energy shells same or different? [closed]

want to understand concept of angular momentum and velocity of electrons in different shells along with their interaction to nuclear force
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1answer
30 views

Can Mach Number Decrease while Flow Velocity Increases?

As in the question statement, I am wondering whether it is possible for Mach number to increase while local flow velocity decreases. I am basing myself on the simple case of an ideal gas, in which: $$...
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1answer
33 views

Orbital Mechanics - How does space debris damage the ISS?

This question is rather self explanatory so I'll keep I succynct. A while back Tim Peake photographed a small crack in the cupola of the ISS, which was reportably a paint fleck that collided with ...
2
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2answers
63 views

Special theory of relativity - relative movement [duplicate]

If Mr. Einstein traveled at 99.99999999% speed of light in one direction and shined light backward, would the photon hang static in the air? Traveling speed of light away from its source that travels ...
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3answers
254 views

Relative Angular Velocity

Two particles describe the same circle of radius 'a' in the same direction with same speed 'v'. What is their relative angular velocity? Angular velocity of both the particles is v/a. It's direction ...
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1answer
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What exactly is “displacement” and “velocity”? [duplicate]

I'm finding two different definitions for what the displacement of an object is: 1) How far the object is from a starting point in a specified direction (direction represented through a straight line ...
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4answers
219 views

How do I find the instantaneous velocity in real life? [closed]

I am learning about Instantaneous speed and velocity in Khan Academy. I understand the concept and calculation, but how do I know the different instantaneous speed at different points in real life?
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1answer
74 views

Vector Identity using Coulomb Gauge in Stancil and Prabhakar's 'Spin Waves'

I'm working through Stancil and Prabhakar's 'Spin Waves', and am stuck with a vector identity which I am not sure how the authors have justified. On page 34, we adopt the use of a scalar potential $\...
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0answers
65 views

Radial Velocity

How does one create a radial velocity curve from only being given: A planet of mass 4 times that of Jupiter travels on an orbit with a = 0.7AU and e= 0.4 around an M = 1.2 solar mass star. Suppose we ...
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2answers
47 views

How to Lift an object at constant velocity vertically

Let's say there is a Table on the floor . I lift the table up in such a way that it keeps going upwards 5 m/s (I kept holding the table every instant). I lifted the table for 3 seconds so it reached ...
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0answers
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One Dimensional Conservative Potential Issue

If a conservative potential in one dimension is shown to be G(x) = 10x^2 Joules, the value of x is in meters. Let there be a particle of mass = 5kg, at distance x=1m , the V1 = 8m/s in the positive ...
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24 views

The velocity component of an object attached to the string

when we try to find the velocity components of an object attached to the string, we always separate the velocity into: the v along the string and the v perpendicular to the string? Why should it be ...
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0answers
19 views

Calculating Velocity of a Projectile being launched from a Solenoid

So a buddy and I are working on a coilgun half for fun/half for a final project. We assembled a prototype using a huge solenoid (probably 3 inch diameter) and 10ish gauge magnet wire and were able to ...