Direct Measurement Videos > Video Library > Corkscrew loop

# Corkscrew loop

### Summary

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This clip shows a looping roller coaster recorded using a high-resolution high-speed camera. Students can measure the position and time for the roller coaster train in different locations. Students can also measure the radius of the loop at different locations. There are several different versions of this video for different purposes, including one version with drag-able, scalable measurement tools.

## Files

Four versions of this video are are available:

Gen 2 DMV player This version has drag-able, scalable measurement tools, and adjustable frame rate. Students can position these rulers to measure the radii of the track at the bottom and top of the loop. The protractor can be scaled by dragging any corner or edge, and positioned by clicking and dragging. Students should scale and position the protractor so that it coincides with the track, as shown at right. The ruler is pre-calibrated, and can be positioned by clicking and dragging.

DMV player This version has embedded measurement tools already overlaid on the video, so students measure from pre-positioned rulers.

### Instructor Note

When teaching with this video, direct students to the student video library, which provides student access to all videos without links to instructor materials and solutions.

download .mp4 version (MP4 Video 26.1MB Feb15 15) This is the same as the video above, with overlaid, pre-positioned rulers.

YouTube This version does not allow frame-by-frame viewing.

## Teaching Materials

Sample questions:

1. Determine the ratio of centripetal force on the third car in the train when it is at the top of the loop compared to the bottom.
2. Determine the apparent weight of a rider when the train is at the bottom of the track, and when it is at the top.
3. Explain why the track is shaped as it is. That is, why is the radius at the bottom of the loop so much larger than it is at the top?
4. What is the ratio of the kinetic energy of the train before the loop compared to the kinetic energy of the train after the loop?