Why should the fence be mounted on the glider so that the "A" end will pass through the photogate first?
Answer
Because individual picket spacings may not be exactly equal, this allows one to read the position of the glider accurately and directly from the fence calibrations in Appendix C.
Because only the edge labeled "A" will trigger the photogate.
No special reason. As long as all measurements use the same leading edge consistently, it doesn't matter which edge it is.
The correct answer is:
Because only the edge labeled "A" will trigger the photogate.
Explanation:
The photogate is a device that measures the time it takes for an object to pass through it. In this case, the glider passing through the photogate is being used to measure its position.
Since the fence has individual picket spacings that may not be exactly equal, it is important to mount the fence on the glider in a way that ensures consistent and accurate measurements.
The "A" end of the fence is designed to trigger the photogate, meaning that it will activate the timer and record the time at that specific position. Mounting the fence so that the "A" end passes through the photogate first ensures that the timer starts recording accurately at that point.
By using the "A" end consistently as the leading edge in all measurements, it allows for precise and direct readings of the glider's position from the fence calibrations provided in Appendix C.
So, the answer "Because only the edge labeled 'A' will trigger the photogate" is the correct choice for why the fence should be mounted on the glider so that the "A" end will pass through the photogate first.