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 Author Topic: Need help ! Please entry !  (Read 16329 times) 0 Members and 1 Guest are viewing this topic. Click to toggle author information(expand message area).
flyvess800
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 « Embed this message on: December 02, 2005, 04:17:15 am »

The tennis balls are kept in a box at constant temperature.At regular inercals,the umpire calls for new balls,because if we use the balls of low presure to limit the speed of rebound,it will be more easily to attack.The teacher asked we 2 do a experiment to considered it,i know we need to use the equation E=mgh,but when we do the experiment, how do i drop 2 balls from a different temperature,how do i draw the graph to include these things~?

JUst need help ! ~ [/b]
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Fu-Kwun Hwang
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 « Embed this message Reply #1 on: December 02, 2005, 10:01:41 am » posted from:Taipei,T'ai-pei,Taiwan

Could you explain it in more detail. I did not understand it!
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nouinou
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 « Embed this message Reply #2 on: December 09, 2005, 05:32:48 am »

:oops: :oops:
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hesham
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 « Embed this message Reply #3 on: February 08, 2006, 02:35:42 pm »

FIRST I WANT TO SAY THAT I AM JUST A HIGH SCHOOL STUDENT SO IAM NOT 100% SURE

IF YOU ARE TRYING TO GET GRAPHS FOR CHANGE IN TEMPERATURE AGAINST BALL REBOUND TRY FIRST USING THE EQUATION FOR IDEAL GAS "PRESSURE IS DIRECTLY PROPORTIONAL TO TEMPERATURE SO IF YOU HEAT A BALL (MAY B IN A WATER BATH)THE PRESSURE WILL INCREASE IN THE BALL(HEAT IT SLOWLY AND SAFELY AT LOW TEMPERATURES OR ELSE IT MAY BURST AND THIS IS HAZARDOUS)

THEN U SHOULD USE THE EQUATIONS FOR NEWTON'S SECOND LAW OF MOTION "CHANGE IN MOMENTUM=MASS *FINAL VELOCITY-MASS*INITIAL VELOCITY.TO GET THE INITIAL VELOCITYYOU SHOULD THROW THE BALL FROM A MEASURED HEIGHT(LETS SAY 10METRE FOR EXAMPLE)THEN BY USING THE EQUATION
USE THE EQUATIONS OF MOTION(THERE ARE 4 OF THEM FIND WHICH ONE IS SUITABLE FOR YOU TO GET THE VELOCITY BEFORE AND AFTER HITTING THE GROUND)
THEN AFTER GETTING THE INITIAL VELOCITY OF THE BALL WHEN IT HITS THE GROUND AND THE FINAL VELOCITY AFTER IT LEAVES THE GROUND USE THE EQUATION TO FIND THE CHANGE IN MOMENTUM AND REMEMBER THAT V IS A VECTOR SO IF THE DIRECTION CHANGES THEN THE SIGN WILL CHANGE FROM POSITIVE TO NEGATIVE.

BY FINDING THE MOMENTUM CHANGE([b:49dee025ae]PLEASE ASK YOUR PHYSICS TEACHER ABOUT HOW [/b:49dee025ae][b:49dee025ae]TO CALCULATE MOMENTUM WITH INELASTIC COLLISIONS[/b:49dee025ae])REPEAT THE EXPERIMENT WITH BALLS OF DIFFERENT TEMPERATURE DRAW A GRAPH OF TEMPERATURE AGAINST CHANGE IN MOMENTUM

[u:49dee025ae][i:49dee025ae][b:49dee025ae]OR[/b:49dee025ae][/i:49dee025ae][/u:49dee025ae]
JUST HEAT THE BALLS AT DIFFERENT TEMPERATURES AND DROP THEM FROM THE SAME HEIGHT AND MEASURE THE HEIGHT THAT THEY REBOUND TO AND DRAW A GRAPH OF THE VALUES OF TEMPERATUR AGAINST HEIGHT THEY REBOUND

HOPE THAT I HAVE HELPED YOU.
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You cannot always have happiness but you can always give happiness. ..."Mother Teresa(1910-1997, Roman Catholic Missionary, 1979 Nobel Peace Prize)"