Is it Possible to Build a Device for Measuring Speeds of Arbitrary Objects?

  • Thread starter koolraj09
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In summary, there are commercially available devices for measuring speeds of objects - some are quite specific like the speedometer of your car and others are very general like the doppler radar the police use to nab speeding motorists. You can even get a speedometer app for a smart-phone that uses (I guess) gps or inertial tools. Simon was wondering if anyone had any suggestions on how to measure the speed of an object. Some possible options include measuring time, distance, or velocity.
  • #1
koolraj09
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Hi all.
I've been thinking of how one can measure the speed (& indirectly velocity, since we know it's direction of travel) of an object. The object is not necessarily an airplane or an automobile since they've their special devices built for velocity measurement.
I was thinking of measuring my speed while me running a few miles or velocity of a ping-pong ball thrown in a particular direction. Can we build a device for measuring speeds of these objects? Or are there already devices for measuring speeds of arbitrary objects?
Cheers.
 
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  • #2
Yes there are commercially available devices for measuring speeds of objects - some are quite specific like the speedometer of your car and others are very general like the doppler radar the police use to nab speeding motorists.

You can even get a speedometer app for a smart-phone that uses (I guess) gps or inertial tools.

So I'm puzzled by your question - surely everyone's heard of a speedo?

Looking at your examples:
I was thinking of measuring my speed while me running a few miles
... sure, you time how lino it takes to pass regulary spaced markers like lamp-posts
or velocity of a ping-pong ball thrown in a particular direction.
photography is usual for this, or a photogate. In general you could use sonar or radar.
 
  • #3
Hi Simon!
As I mentioned in the post I know about the speedometer of a car or venturi-meter for measuring the speed of an airplane.
Yes the answer that I was looking for lies in your second quote -
Photography, Photogate,sonar or radar. Thanks!
 
  • #4
Baseball pitchers throw baseballs that are sometimes said to exceed 100mph. How do you imagine that is measured?
 
  • #5
I think that's kinda what koolraj09 is asking about.

By filming them with a high speed camera against a stripy background then comparing the shots frame-by-frame. Knowing the distance the ball travels between shots (because you know the distance between the stripes) and the time between shots tells you the speed. I thought everyone was familiar with this method but it seems another one of my assumptions bites the dust :)

Clearly not everyone has seen Mythusters ...

That would be the photography option - there is always just pointing a radar gun at the pitcher. The pitcher could pitch the ball through a photogate - knowing the time the gate is interrupted and the diameter of the ball tells you the speed.

In general, anything that allows you to divide distance traveled by the travel time will tell you the speed. The idea is to pick one that suits the object in question.
 
  • #6
Enter into the Google search term box “baseball speed radar” and lo and behold, how many different methods and types of speed measuring equipment are available? To measure baseball speeds, one typically stands behind the catcher with a hand-held doppler radar. Some units can detect and measure ping pong balls, too!

Mount the radar on the glove to measure baseball speed:
http://gloveradar.com/htdocs/gr_3bcoach.html

Mount the radar on the bat to measure the bat speed:
“The Swing Speed Radar™ from Sport Sensor measures baseball/softball bat speed to help players optimize their swing mechanics. Determine your optimum swing and bat selection for your best distance, quickness and bat control/ball contact.”
http://www.eastbay.com/product/mode...=SEM-_-Engine-_-Google-_-Plusbox&siorigin=pla

Here the sensor is inertial (that is, not radar) and totally contained inside the baseball:
The Laser-Ball Baseball LB-10 can sense if it is being held in your hand and you can hold the ball naturally. Once you pitch the Laser Ball Baseball Radar, it will notice immediately. When the Base Ball Laserball LB 10 is caught, the speed of the Laser Ball is displayed instantly.
http://www.opticsplanet.com/primary-simulation-laser-ball.html

There are laser operated speed measuring equipments as well.
 
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  • #7
Hey thanks simon & bobby..
 
  • #8
@Bobby: Ooooh - better than I suspected :)
@koolraj: no worries - we have all asked funny (to others) sounding questions before ;) Even ones which, once we have the answer, we go "Doh!"
 

FAQ: Is it Possible to Build a Device for Measuring Speeds of Arbitrary Objects?

What is the difference between speed and velocity?

Speed and velocity are often used interchangeably, but they have different meanings in physics. Speed is a measure of how fast an object is moving, while velocity is a measure of both speed and direction. In other words, velocity takes into account the direction of an object's motion, while speed does not.

How is speed/velocity measured?

Speed and velocity can be measured using different methods, depending on the situation. For example, the speed of a car can be measured using a radar gun, while the velocity of a rocket can be calculated using its change in position over time. In general, speed and velocity are measured in units of distance per unit of time, such as meters per second or miles per hour.

What is the difference between average speed/velocity and instantaneous speed/velocity?

Average speed/velocity is calculated by dividing the total distance traveled by the total time taken. This gives an overall picture of an object's speed/velocity over a period of time. On the other hand, instantaneous speed/velocity is the speed/velocity at a specific moment in time. It can be found by calculating the slope of an object's position-time graph at a particular point.

How do changes in speed/velocity affect an object's motion?

Changes in speed/velocity can have a significant impact on an object's motion. If an object's speed/velocity increases, it will cover more distance in the same amount of time, resulting in a longer displacement. Similarly, if an object's speed/velocity decreases, it will cover less distance in the same amount of time, resulting in a shorter displacement. Changes in direction can also affect an object's motion, as velocity takes into account both speed and direction.

How does the measurement of speed/velocity impact scientific research and real-world applications?

The accurate measurement of speed/velocity is crucial in many scientific fields, such as physics, engineering, and astronomy. It allows researchers to understand and predict the behavior of moving objects, which is essential for developing new technologies and making advancements in various industries. In real-world applications, speed/velocity measurements are used in transportation, sports, and many other areas to improve efficiency and safety.

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