Silly Wonderings
Have you ever wondered why an insect FLYING inside a car doesn't end up being WHACKED on the back windshield considering a car's speed is at least 60 kph on the average?
Silly me, when that first occured to me I didn't realize at once that it's just simply because an air-conditioned car is an isolated and closed-system. :D
Silly me, when that first occured to me I didn't realize at once that it's just simply because an air-conditioned car is an isolated and closed-system. :D
mood: geeky
the wind blew @ 12:40 PM
12 whispers in the wind:
e bakit sa jeep?
hindi ah, unless nakakapit cya sayo :p
i think i was the one who opened this topic in our past discussions. hanggang ngayon hindi pa rin ako convinced sa mga argumentong narinig ko.
the car is not an isolated system because you cannot guarantee that there is no energy exchange at the boundary. nor is it a closed system because in actuality there is an exchange of matter. di ba ang hangin ng aircon galing sa labas ng kotse?
what if you had a thermos bottle inside the car and the car is moving at 80 km/h. anong mangyayari sa langaw sa loob, assuming that it is hovering and not touching the inner surface of the thermos bottle?
paano natin malalaman e hindi naman tayo langaw?
maybe we should refer this to the experts.
Nakita ko yung link na to to explain --
Bird flying inside a car
I will make a guess before I read jae's link...
isn't everything (including motion) relative to the frame of reference? er... I don't know where i'm going with this so im going with... wind resistance and momentum? I mean, if (assuming there is no wind resistance at all) a fly lands on the car before it moves, once the car starts moving, they'd have the same initial velocity, and if indeed there was no resistance, the fly could umm.. fly up and, theoretically, keep on going at the same speed as the car (if the car is no longer accelerating). Since the windshield of a car or jeep effectively cuts the resistance away, the fly can "keep up" with the car with little effort...
my god that was geeky!!! and im probably wrong too... hehe
ack! I was wrong nga! should have followed my first line of thought.. hehe
Actually i don't recall ever bringing this up with anyone except with Mars. We agreed on one thing, that there is no wind resistance inside a car (like what alekos speculated) since it acts as a closed system... but i never confirmed if it was indeed the right explanation. I just thought it was scientific enough.
Yup I of course thought it wasn't a closed-system when it comes to temperature because there is still an exchange of heat energy between the car and its surroundings. But although the air blowing from the air-con still comes from the outside, the closed car keeps the air inside steady therefore maintaining an isolated atmosphere with normal air resistance.
cool! hahaha! geeks! hahaha!Ü
Okay, here's the explanation from jae's link: "When a bird flies inside a moving car, the air within the car is moving with the car, and with the car's speed relative to the earth outside. However the important thing to the flying of a bird is the speed of the air over its wings. So the bird needs to fly through the air of the car just as it would fly through the stationary air outside the car... It's speed relative to the ground changes depending on the wind, but it's speed in the air remains the same... As far as the bird and the people in the car are concerned there is no difference to flying in a car as there is to flying in still air outside the car."
hehe ang saya! :D
Guess that means that inside an open-air vehicle, jumping will make you fall off...
cel: hehe :) ...fall off and follow a trajectory path relative to earth (projectile motion) since you have an initial horizontal-component velocity. :)
armi: I've been thinking... I'm pretty sure it was me who introduced the idea, i was so amused i can even remember feeling silly and geeky the first time it popped up in my head. The insect was a fly. Now I remember I had presented it to you but I just can't recall how the conversation went. Maybe because I considered it already resolved after my conversation with Mars.
the bird in the car nailed it.
yeheeeey!
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