the watermelon or the penny?

[xouper]

This week's science quiz:


If you drop a watermelon and a penny (at the same time) from an airplane at 13,000 feet above the ground, which one will hit the ground first?

Answer: the watermelon. A typical watermelon will fall at about 120 to 130 mph, whereas a penny will plummet at less than half that speed.


If a peregrine falcon and skydiver leave an airplane at 13,000 feet above ground (agl) and dive headfirst in a race to 3000 feet agl, which one will get there first?

Answer: the peregrine. A typical skydiver will have difficulty going much faster than 180 mph vertically, even in a maximum head down dive, whereas a peregrine can dive over 200 mph straight down.

[livius drusus]

I got the first one wrong I blame Galileo and the second one right.

More questions! More questions! :cannon:

[viscousmemories]

I got the first one wrong and didn't even have a guess on the second. :blush:

[Ex-zombie]

I got them both right! Ha. Ha. Ha. I am a very good guesser. :cool:

[Dragar]

I got them both right.

But...I have just finished a course in fluid dynamics, and learning about theories of drag and streamlining! :graduate:

Well, okay. That's premature. It's more like this:

:student:

[JoeP]

I got them both right because they were easy. :clever: :runaway:

[The Lone Ranger]

You and a friend synchronize your watches, then you jump into a spacecraft and take off for Alpha Centauri. Your super-advanced spaceship instantly accelerates to 99% of the speed of light. Upon reaching the Alpha Centauri system, you immediately turn around and head back to Earth, still going at 99% of the speed of light.

When you return to Earth, is your watch still synchronized with your friend's? If not, has he experienced more elapsed time, or have you?

From your friend's perspective, at least 8 years will have passed from the time you set out until the time you returned. But you would have experienced the passage of only a few weeks' time during your high-speed flight. In other words, upon your return you would find that you had, in effect, traveled 8 years into the future.

[Dingfod]

Doesn't matter, both you and your watch would be pretty much two dimensional after instantly accelerating to 99% of the speed of light. I cannot imagine a watch that would continue to function under those conditions... okay, maybe a Timex.

[Ymir's blood]

You and a friend synchronize your watches, then you jump into a spacecraft and take off for Alpha Centauri. Your super-advanced spaceship instantly accelerates to 99% of the speed of light. Upon reaching the Alpha Centauri system, you immediately turn around and head back to Earth, still going at 99% of the speed of light.

When you return to Earth, is your watch still synchronized with your friend's? If not, has he experienced more elapsed time, or have you?

From your friend's perspective, at least 8 years will have passed from the time you set out until the time you returned. But you would have experienced the passage of only a few weeks' time during your high-speed flight. In other words, upon your return you would find that you had, in effect, traveled 8 years into the future.
Heinlein had a story using that idea, coupled with telepathy. A guy on the ship had a telepathic link with his twin brother who stayed on Earth. As the story progressed, the Earthbound brother aged far more rapidly than the protagonist (on the ship.)

[maddog]

You and a friend synchronize your watches, then you jump into a spacecraft and take off for Alpha Centauri. Your super-advanced spaceship instantly accelerates to 99% of the speed of light. Upon reaching the Alpha Centauri system, you immediately turn around and head back to Earth, still going at 99% of the speed of light.

When you return to Earth, is your watch still synchronized with your friend's? If not, has he experienced more elapsed time, or have you?

From your friend's perspective, at least 8 years will have passed from the time you set out until the time you returned. But you would have experienced the passage of only a few weeks' time during your high-speed flight. In other words, upon your return you would find that you had, in effect, traveled 8 years into the future.
Wow, I seriously misread this! Just goes to show how my mind sees ambiguity everywhere . . . why are you all ASSUMING your friend stays put? Nothing says he didn't get into your same ship! Or get into a ship going at some other speed, or even in the opposite direction!!

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