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Three assertions, Which are true? Which are false? Why?
*mipadi*
post Mar 9 2006, 10:23 AM
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I'm going to make three assertions. Which of these are true, which are false, and why?

Assertion 1

Assume you have a cute little bunny rabbit, and you place her thirty feet away from a carrot. The bunny really wants the carrot, but she can only get to it by jumping halfway to the carry each time she hops. Clearly the poor bunny will never make it to the carrot, because the distance between her and the carrot can be divided in half an infinite number of times (i.e. no matter where she is, the distance left can always be divided in two).

Now assume that the bunny can move however she wants. She still will never reach the carrot, because to do so, she must move through the same points as in the previous example; but as noted, there are an infinite number of points to move through, which means the bunny can never, ever reach that carrot. In fact, to move at all, the bunny must move through an infinite number of points; so unfortunately, the bunny is rooted to whatever spot she starts out from. Poor bunny.

Assertion 2

I'm mad at you, and I throw a rock at your head. You run away and try to avoid the rock. But why even bother? Assume I throw the rock at you. Now, take note of the position of that rock at a single instance of time. It's not moving, is it? At a specific moment in time, the rock has a position, but it does not have time to move and so is at rest. During each instance of time, it is at rest for the same reason. Therefore, the rock is always at rest, and it never moves. Therefore, it is foolish for you to run away.

Assertion 3

Assume a tortoise and a sprinter race. The sprinter is a nice guy and knows he can beat the tortoise, so he lets the tortoise start a hundred feet ahead of him. The sprinter and tortoise then both begin the race and, upon reaching their maximum speed, continue running at that speed. Clearly the tortoise is much, much slower than the sprinter—but will the sprinter ever catch up to the tortoise? Unfortunately, the answer is no, he won't.

Assume the sprinter has run a hundred feet, and thus reached the tortoise's starting point. In this time, the tortoise has moved a foot, which still means he is beating the sprinter by a foot. The sprinter than runs another foot, catching up to the tortoise's position—or so it seems, but remember that the tortoise has moved during this period of time, too, so he is still a tiny bit ahead of the sprinter. The sprinter takes a tiny bit of time to reach this point, but in this period of time, the tortoise has moved forward a tiny bit more again. Thus, whenever the sprinter reaches a point where the tortoise has been, the tortoise has always moved a bit farther forward. No matter how fast the sprinter runs, the tortoise is always ahead. Wasn't he foolish for giving that tortoise a head start?!
 

Posts in this topic
mipadi   Three assertions   Mar 9 2006, 10:23 AM
je like french   no real opinion, but i was wondering where the las...   Mar 9 2006, 08:16 PM
mipadi   QUOTE(je like french @ Mar 9 2006, 8:16 P...   Mar 9 2006, 08:31 PM
RiC3xBoy   I am a bit confused by the 2nd one. It's prob ...   Mar 9 2006, 08:49 PM
kryogenix   I guess for the first one, the graph of the functi...   Mar 9 2006, 09:12 PM
wind&fire   false for the first one where the rabbits' mov...   Mar 9 2006, 09:47 PM
salcha   I'm assuming Assertion 1 is true, because of t...   Mar 9 2006, 11:49 PM
racoons > you   point 1 is technically true, because of infinitely...   Mar 10 2006, 05:16 PM
mipadi   Whoops, almost forgot about this. All the asserti...   Apr 4 2006, 11:01 PM
Ice Cream 4 U   ^Man, I just typed a long response. Then I saw tha...   Apr 4 2006, 11:11 PM


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