[b]ChallangeA: Estimating the plane's height by its sound delay.
ChallangeB: Estimating the plane's speed with a video shot and trigonometry[/b]
[b]Materials:[/b]
Long ruler(≥30cm)
Tablet or Smartphone wit hcamera and apps for movie cutting & noise analysis
[b]Setup:[/b]
1. Position the camera exactly facing up (internal G-Sensors or a plumb-bob may help).
2. Fix a long ruler in front of the video camera.
3. Determine the distance between the ruler and the camera.
4. Film an airplane at approach from below.
[b]Determining the plane’s height:[/b]
A plane should be loudest when directly above us. Therefore analyze the video and note the time when the plane passed exactly overhead. Then analyze the soundtrack of the video clip and determine at which timestamp the plane was loudest. With the time difference in seconds the height can be determined: h_plane= ∆t ∙ v_sonic
[b]Determining the plane’s speed:[/b]
Using simple trigonometry (Intercept Theorems) delivers:
[color=#0a971e]h_ruler[/color]/[color=#c51414]d_ruler[/color] =[color=#1551b5]h_plane[/color]/[b]d_plane[/b]
Students may find these relations on their own or with little hints.
