hvis man styrter og hopper?

fuldstændigt off topic, men har en rødvinsdiskution, som kræver hurtigt svar.

Jeg sidder med en kvinde, som hårdnakket mener, at hvis man nu sidder i en flyver eller elevator, der styrter ned, så kan man bare hoppe lige inden man rammer jorden.

Jeg ved, at man ikke bliver mindre fladmast af den grund, men mangler lidt argumentation fra newton.

Er der nogen der ligger inde med en fysisk forklaring, som en blondine kan forstå? Den skal gerne være simpel og overbevisende.

al hjælp er meget værdsat. Og jeg har sagt, at I ved alt herinde, så skuf mig ikke.

Se mythbusters - de har "bustet" den myte ;-)

Du falder med samme hastighed som flyet, elevatoren eller whatever, og lander derfor også med den givne hastighed = SMASK!


Det er Episode 17: Elevator of Death, Levitation Machine - btw:

Jamie and Adam test their luck in the elevator of death. If an elevator suddenly falls, can you save yourself in the nick of time by jumping just before it hits bottom? Or will this leap of faith have disastrous consequences for Buster? Then, let the competition begin. The MythBusters challenge their imaginations and their building skills as they each try to create a homemade levitation machine. Will their appliances keep them afloat or leave them flat?

Haha, det er sådan noget man ikke kan forklare blondiner :-) (no offense mod hende, men sådan er det altså bare hehe)

Mvh.

Area: Physics
Posted By: Philip Plait, Astronomer/Programmer
Date: Thu Dec 19 14:54:51 1996
Message ID: 849198663.Ph


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You''d think that would work, right? You''re in a falling elevator, plummeting downward. Just before impact with the ground, you jump one centimeter high. As the elevator crashes, you only fall that one centimeter and you''re safe!

Or are you? Remember, when you jump that one centimeter, that is one centimeter relative to the floor of the elevator! The elevator is still falling, and so are you! Imagine the elevator floor is glass, and you can see the ground rushing up at you. That one centimeter jump doesn''t look like it''ll help much now, does it? All you''ve really done is add another centimeter to the length of your fall. Your body will impact at the same speed, only a fraction of a second later.

Now if you are trying to negate the speed of your fall by jumping upwards, that won''t work well either. In free fall, you fall 10 meters in the first second, 20 in the next second (for a total of 30 meters), 30 the next (total of 60) and so on, falling 10 meters per second faster for every second of the drop. Now, friction and air resistance will eventually stop the downward acceleration. A human freely falling tends to peak at about 180 kilometers per hour, or about 50 meters a second. That''s fast, about twice as fast as a car on a highway. An elevator might do more in a big high rise. Now try jumping that fast! I am guessing that the most you can jump straight up is a meter or two per second.

Think of it this way. Instead of jumping up, think about how hard it is when you hit the ground after jumping down off a wall. This is the same problem as the elevator, but in reverse. After jumping even a couple of meters your knees hurt, right? Now imagine falling 20 meters! Ouch!

Takker for svaret! Klasse. Blondinen fattede det, men jeg skulle hilse og sige fuck dig til MoPe :-)

Hvis du forestiller dig du falder med 200 km./t. og du har en springkraft på (lige når du har hoppet hvor den er størst) 50 km./t. vil du stadig lande med 150 km./t.

Ved ikke om det var en forkortet version af Mads Møllers indlæg, men dette burde de fleste kunne forstå.

Hehe, tak skal du have :-)

Hvis du befinder dig i en flyvemaskine i frit fald, svarer det til at du er vægtløs. Det er faktisk den eneste måde hvorpå vægtløs tilstand kan simuleres/trænes.

Du kan derfor ikke "sætte af"

Dertil skal lægges at den meget extreme springkraft, der skal genereres virker på elevatoren (antaget at den kunne virke på elvatoren) ..... dermed ville en del af kraften "bruges" på yderligere at accelere elevatoren nedad.... istedet for af decelerere kroppen i nedadgående retning.