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Location:
Brisbane
Registered:
October 2004
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Re: Physicist please read.
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Thu, 07 April 2005 06:38
 
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WTF?!?! this is stupid....
the ball has a mass which is not important since we're not considering air resistance... and a velocity at any point in time... barrys hand also has a velocity at any point in time, but it's only important up to the point where the ball leaves barrys hand...
gravity is constant 9.8m/s/s (meters per second, per second) on earth, air resistance is nill...
newtons 3rd law is only true for systems in equilibrium, IE, stationary, or constant speed. as soon as forces are unbalanced ie, barry hurls the ball up, then obviously there's accelletarion for a time, say barry accelerates the ball to a speed of 20m/s immediatly after the ball leaves barrys hand it starts to slow down at the rate which gravity acts on it, 9.8m/s/s there for it will reach it's maximum height of 20.29m at t=2.04sec (where t=0 is where the ball left barrys hand)
the moral of the story is:
Kim is right, but she's talking about when barry throws the ball,
Barry is right, but he's talking about the ball stationary in his hand.
kathy is both right and wrong, she's wrong 'cause she says the others are wrong, but she's right 'cause in this case the reactive force to barrys hand is the weight of the ball multiplied by the force due to gravity. hence, as kim stated if barry overcomes this force, then he'll accelerate the ball.
basically your all right, but your talking about the senario at different stages, or saying it in a different way...
anyone care to argue that, can go and unbalance their forces over a cliff
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| | Subject | Poster | Date |
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Physicist please read.
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T APLUS 22 | Thu, 07 April 2005 05:26 |
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Re: Physicist please read.
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Corona RT142 | Thu, 07 April 2005 05:28 |
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Re: Physicist please read.
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st184 sillycar | Thu, 07 April 2005 05:34 |
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Re: Physicist please read.
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Phrozen_Death | Thu, 07 April 2005 06:09 |
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Re: Physicist please read.
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river | Thu, 07 April 2005 06:19 |
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Re: Physicist please read.
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hickoz_bro | Thu, 07 April 2005 06:38 |
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Re: Physicist please read.
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T APLUS 22 | Thu, 07 April 2005 15:02 |
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Re: Physicist please read.
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st184 sillycar | Fri, 08 April 2005 00:54 |
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Re: Physicist please read.
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THE WITZL | Fri, 08 April 2005 03:33 |
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Re: Physicist please read.
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Phrozen_Death | Fri, 08 April 2005 03:51 |
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Re: Physicist please read.
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st184 sillycar | Fri, 08 April 2005 04:07 |
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Re: Physicist please read.
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hickoz_bro | Fri, 08 April 2005 09:24 |
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Re: Physicist please read.
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river | Fri, 08 April 2005 10:36 |
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Re: Physicist please read.
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hickoz_bro | Sat, 09 April 2005 08:10 |
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Re: Physicist please read.
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T APLUS 22 | Sun, 10 April 2005 08:38 |
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Re: Physicist please read.
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hickoz_bro | Sun, 10 April 2005 10:47 |
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Re: Physicist please read.
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river | Tue, 12 April 2005 06:35 |
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Re: Physicist please read.
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T APLUS 22 | Tue, 12 April 2005 13:35 |
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Re: Physicist please read.
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b1gb3n | Mon, 11 April 2005 01:49 |
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Re: Physicist please read.
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T APLUS 22 | Mon, 11 April 2005 08:43 |
