High-speed cameras are excellent tools for creating slow-motion recordings of fast-paced action, such as sports replays or dramatic wildlife shots. In addition, a high-speed camera can be used to measure the speed of a falling object or projectile. Although cameras with a lower frame rate can be used for similar purpose, their slower exposure rates will often create a blurred image, resulting in a less accurate measurement.
Instructions
1. Create a measured grid using your white cloth. To do this, mark out the cloth in increments of 1 inch or less. Using smaller increments will allow for greater accuracy. Divide the cloth into whatever increment amount you choose using a measuring tape and marker. Using a T-square will allow you to create precise 90-degree angles throughout the grid.
2. Hang your measured grid against a flat wall. This will serve as the backdrop, in front of which you'll fire your projectile. The measured grid should be hung in a bright room, to allow for an increased level of visibility. Most high-speed cameras require significantly more light than a low-speed camera to achieve a clear exposure.
3. Determine the frame rate of your high-speed camera by referring to the camera's operating manual. Some high-speed cameras feature adjustable frame rates, and can range from 60 frames per second (the bare minimum to receive the classification of "high speed"), to 500 frames per second, to an astonishing 17,000 frames per second. Higher frame rates will typically equate to a more expensive camera.
4. Point your camera toward the measured grid and begin recording. Fire your projectile through the room, ensuring that it travels in a line parallel to the grid. Failing to maintain a parallel path of motion will compromise the accuracy of your speed measurement.
5. Analyze the footage taken by the camera. Multiply the distance traveled by the object from one frame to the next by your camera's frame rate. This will determine the distance that the object has traveled in one second. For example, your object covers a distance of 34.5 inches in a single frame, with a recording speed of 200 frame per second. This would indicate that the object is traveling at 6,900 inches per second. Multiply this number by .0568182 to convert it to miles per hour. In this case, your object traveled 392 miles per hour.
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