Rhett Allain rechnet auf Wired aus, ob Vogelscheiße die Windschutzscheibe eines parkenden Autos knacken kann. Im Posting fallen dann so super Sätze wie „If the density of the poop is 1000 kg/m3 (like water) then it would have a mass of 0.0157 kg“ oder auch „If the poop is at terminal speed (and thus a constant speed), then the magnitudes of these two forces must be equal“ Physics is Fun!
What starting info do I have?
The bird poop made a 4 inch diameter spot on car. Not sure how thick this spot was.
The car was parked.
That is about all I have. So maybe I can make some assumptions:
- I am going to assume the starting height of the poop was large enough such that the poop was traveling at terminal speed.
- Falling poop is spherical. Yes, I know rain doesn’t fall this way (rain drops aren’t shaped like I thought) but you have to start somewhere.
- The density of poop is the same as water (should be close enough for this estimation).
- What is the compressive strength of laminate glass (for a windshield)? I couldn’t find a definite answer, but it seems 25 MPa to 100 MPa seems plausible (although it could be much higher). For this case, I am going to assume 50 MPa – maybe there was a slight crack previously that made the glass weaker.