Can instantaneous velocity be measured

In practice what you do with a macroscopic object is observe it and work out an velocity that fits a model of it's trajectory that you have.

How do I remove the error? Well I can't. I can only average it out. But there will always be some error because I did not have exact measurements of the velocities to fit the equations to. We can reduce the margin of error in our parameters by fitting more data to it, but it will never quite disappear. The uncertainty principle which doesn't matter much for large everyday scale objects has a more extreme effect. It means that once I measure something like velocity, that measurement process itself will mean that I have changed the value to something else that is more or less random.

The very act of measuring something changes it. So at a quantum mechanical level, just trying to determine something's velocity will change the velocity to some unknown value. So the margin of error cannot be reduced by making repeated measurements, as all repeated measurements do is introduce more uncertainty, not less. And because uncertainty is measuring e.

So I can't even fit my motion to a fixed path using repeated measurements. Si quantum theory is fundamentally different in this sense. Here is another possible method with a couple of severe limitations, but probably acceptable for educational purposes: accelerometer. If the initial speed of an object is zero first limitation and the accelerometer does not have any errors second limitation , the accelerometer output will let you calculate a precise instantaneous speed of the object at any moment in time as:.

I am not selling anything here, but if you can afford a 3-axis accelerometer, you can track instantaneous speed of an object in 3D space. With real life accelerometers, the error accumulation will not allow you to measure the speed accurately beyond a short time window after the start. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. To determine the average velocity of the particle between 1.

What is the speed of the particle at these times? Strategy The instantaneous velocity is the derivative of the position function and the speed is the magnitude of the instantaneous velocity. The speed gives the magnitude of the velocity. By graphing the position, velocity, and speed as functions of time, we can understand these concepts visually Figure 3.

The reversal of direction can also be seen in b at 0. But in c , however, its speed is positive and remains positive throughout the travel time. We can also interpret velocity as the slope of the position-versus-time graph. The slope of x t is decreasing toward zero, becoming zero at 0.

This analysis of comparing the graphs of position, velocity, and speed helps catch errors in calculations. The graphs must be consistent with each other and help interpret the calculations.

The slope of the position graph is the velocity. A rough comparison of the slopes of the tangent lines in a at 0. Speed is always a positive number. Previous Next. Order a print copy As an Amazon Associate we earn from qualifying purchases. We recommend using a citation tool such as this one. Authors: William Moebs, Samuel J. Such a parameterization is called an arc length parameterization. It is nice to work with functions parameterized by arc length, because computing the arc length is easy.

The curvature of a straight line is zero. The curvature of a curve at a point is normally a scalar quantity, that is, it is expressed by a single real number. In geometry, the center of curvature of a curve is found at a point that is at a distance from the curve equal to the radius of curvature lying on the normal vector. It is the point at infinity if the curvature is zero. The osculating circle to the curve is centered at the centre of curvature. A unit normal vector of a curve, by its definition, is perpendicular to the curve at given point.

Furthermore, a normal vector points towards the center of curvature, and the derivative of tangent vector also points towards the center of curvature. In other words, we can conclude that this vlue of x gives us the maximum value of k x.

Begin typing your search term above and press enter to search. Press ESC to cancel. Skip to content Home What is the equation for instantaneous velocity? Ben Davis May 31, What is the equation for instantaneous velocity?

What is an example of instantaneous velocity? What is instantaneous velocity and average velocity? How do you find instantaneous velocity on a graph? What is the symbol for instantaneous velocity?

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