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#61
08-07-2007, 08:53 PM
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Re: Need help devising an easy physics question that sounds really har
[ QUOTE ]
[ QUOTE ] [ QUOTE ] [ QUOTE ] [ QUOTE ] A man drops his prize golden elephant statue (10 kg) out a window by mistake. Immediately after realizing his mistake (5 seconds later), the man (100 kg) in a lapse of judgment dives out the window to save his statue. Will he catch the statue in time? If not, how much will he miss it by? Answers below in green: <font color="green"> No, 5 second</font> [/ QUOTE ] you have to specify a falling distance for that question not to be way too easy. any decent test taker with no knowledge of physics should be able to figure that out based on the info given. [/ QUOTE ] I'll show my stupidity. I have hardly even any high school physiscs but this seems counter intuitive to me. Wouldn't the objects mass density be a a factor causing the, most likely, compact elephant thing to fall faster? [/ QUOTE ] no. you never got to throw a bowling ball and an egg out of the window in school? [/ QUOTE ] I must've been sick that day. [img]/images/graemlins/smile.gif[/img] I have however thrown a feather and a stone out a window and I swear to the stone dropped faster. Is the object's shape relevant? God, I feel like a fourh grader. [/ QUOTE ] the reason they fall at different speeds is wind resistance. In a vacuum the feather and the stone would fall at the same speed. 
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#62
08-07-2007, 09:02 PM
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Re: Need help devising an easy physics question that sounds really har
[ QUOTE ]
[ QUOTE ] [ QUOTE ] [ QUOTE ] [ QUOTE ] [ QUOTE ] A man drops his prize golden elephant statue (10 kg) out a window by mistake. Immediately after realizing his mistake (5 seconds later), the man (100 kg) in a lapse of judgment dives out the window to save his statue. Will he catch the statue in time? If not, how much will he miss it by? Answers below in green: <font color="green"> No, 5 second</font> [/ QUOTE ] you have to specify a falling distance for that question not to be way too easy. any decent test taker with no knowledge of physics should be able to figure that out based on the info given. [/ QUOTE ] I'll show my stupidity. I have hardly even any high school physiscs but this seems counter intuitive to me. Wouldn't the objects mass density be a a factor causing the, most likely, compact elephant thing to fall faster? [/ QUOTE ] no. you never got to throw a bowling ball and an egg out of the window in school? [/ QUOTE ] I must've been sick that day. [img]/images/graemlins/smile.gif[/img] I have however thrown a feather and a stone out a window and I swear to the stone dropped faster. Is the object's shape relevant? God, I feel like a fourh grader. [/ QUOTE ] the reason they fall at different speeds is wind resistance. In a vacuum the feather and the stone would fall at the same speed. [/ QUOTE ] Yeah, even I learned that one. But wouldn't the man be subject to air resistance as well? Obviously to a far lesser degree than the feather but still more than the statue.
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#63
08-07-2007, 09:05 PM
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Re: Need help devising an easy physics question that sounds really har
what goes up must come down ?
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#64
08-07-2007, 09:33 PM
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Re: Need help devising an easy physics question that sounds really har
[ QUOTE ]
Ask him what the term for the third derivative of position is. When he calls you a jerk, tell him there's no need to get nasty. [/ QUOTE ] No love for this whatsoever??? Well, I suppose you should do something definitional. That way to anyone with a passing knowlege of the constant or phenomenon in question the answer will be obvious, but to those who don't know it there's no way to answer it. Maybe some questions like these: 1. You are trying to determine how deep a well is, but its too dark to see down. You drop a pebble in the well and use your stop watch to time it. You hear a spash one scond after you let go. About how deep is the well? (a) 10 feet (b) 30 feet (c) 100 feet (d) 300 feet The answer is (b). 2. How many atoms are in one kilogram of Hydrogen? (a) 3.0 * 10^8 (b) 6.0 * 10^23 (c) 1.0 * 10^81 (d) a billion The answer is (b). Or you could make it Helium, and the answer is 1.5 *10^23, but it should be obvious from the order of magnitude alone. 3. If you were to view a Hydrogen atom in its ground state, you would most likely find an electron: (a) only in its excited state, a ground state Hydrogen atom has no electron (b) in the 1s1 orbital (c) in the 2p2 orbital (d) orbiting the neuclus at a distance of 1 atomic unit The answer is (b). Stuff like that.
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#65
08-07-2007, 09:53 PM
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Re: Need help devising an easy physics question that sounds really har
[ QUOTE ]
1. You are trying to determine how deep a well is, but its too dark to see down. You drop a pebble in the well and use your stop watch to time it. You hear a spash one scond after you let go. About how deep is the well? (a) 10 feet (b) 30 feet (c) 100 feet (d) 300 feet The answer is (b). [/ QUOTE ] No thats the velocity (32 ft/s). The displacement is 16 ft. .5*32*1^2
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#66
08-07-2007, 09:56 PM
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Re: Need help devising an easy physics question that sounds really har
[ QUOTE ]
[ QUOTE ] 1. You are trying to determine how deep a well is, but its too dark to see down. You drop a pebble in the well and use your stop watch to time it. You hear a spash one scond after you let go. About how deep is the well? (a) 10 feet (b) 30 feet (c) 100 feet (d) 300 feet The answer is (b). [/ QUOTE ] No thats the velocity (32 ft/s). The displacement is 16 ft. .5*32*1^2 [/ QUOTE ] Yep, I typed it wrong.
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#67
08-08-2007, 03:15 AM
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Re: Need help devising an easy physics question that sounds really har
[ QUOTE ]
[ QUOTE ] A dalmatian (20 kg) is dropped 20 meters into a vat of lime Jello. When it enters the Jello, it decelerates and comes to a stop 10 m deep. What is the total Jello force acting upon the dalmatian? a) 100 Joules b) 200 J c) 400 J d) 800 J [/ QUOTE ] I think I understand what you're trying to say, but wtf? [/ QUOTE ] It is the TOTALLLLL Jello Force... or TJF as we say in the Physics community.
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#68
08-08-2007, 07:10 AM
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Re: Need help devising an easy physics question that sounds really har
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#69
08-08-2007, 02:54 PM
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Re: Need help devising an easy physics question that sounds really har
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#70
08-08-2007, 05:18 PM
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Re: Need help devising an easy physics question that sounds really har
[ QUOTE ]
Okay, my post has seemingly resulted in mass confusion, so I'll work through my answer. Force is mass times acceleration, so if you know the acceleration the Jello imparts on the dog, you get force. First, I determined the speed the dog was traveling at when it reached the Jello: Vf^2 = Vi^2 + 2ad a = 10 (I kept it simple) Vi = 0 d = 20 Vf^2 = 400 so Vf = 20. I used the same equation to determine the acceleration of the dog in Jello: Vf^2 = Vi^2 + 2ad Vf = 0 Vi = 20 d = 10 0 = 400 + 20a Therefore, a = -20 m/s. Then, it's just the force equation: F = ma m = 20 a = 20 F = 400 [/ QUOTE ] You made this so much harder than it needs to be. Potential energy FTW.
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