Calculating Speed Using Trigonometry


Through this project, students will use trigonometry to calculate the speed of a runner. By measuring time, distance, and angles, the students will be able to determine the speed of a moving object.


Project by:
Luke Hanley, Vincent Bett, and Nico Lusardo.


 For this project, one would need a protractor, a pointer and a timer. We laser cut wood to form a protractor and modified a straw to act as the pointer. We used the timer in our phone to measure the time. 
This project can also be done using a regular protractor and a stopwatch.
To measure the speed of an abject, an observer should stand at a certain known distance from the path of the object. Then as the speeding object passses through, the observer should measure the change in angle of the pointer and the time it takes for the angle to change. The observer should then use trigonometry ratios to determine the distance covered by the speeding object and then the speed. 
One thing to note is that the faster the object, the shorter the measured time.

Initial Action Plan

We designed an experiment to determine the speed of a runner without simply measuring the time it takes to run a specific distance. In this experiment, the speed can be calculated by an observer from a distance.

Protractor Construction
Angle Calculation
Speed Calculation

 In order for a student to calculate the speed of the object, the student needs to have knowledge of trigonometry, more specifically the student needs to know how to use trigonometric ratios to calculate distance. Then after finding the distance covered by the object, the student needs to apply the formula for calculating speed in order to find speed. 
This part also tests a students ability to convert the results to the standard SI unit of speed.

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