Comments for PoFelix Pages http://pofelix.wordpress.com Mathematics Dialogue Sat, 14 Nov 2009 16:44:03 +0000 http://wordpress.com/ hourly 1 Comment on 跑步的物理 by KAKAKI http://pofelix.wordpress.com/2009/11/11/%e8%b7%91%e6%ad%a5%e7%9a%84%e7%89%a9%e7%90%86/#comment-1016 KAKAKI Sat, 14 Nov 2009 16:44:03 +0000 http://pofelix.wordpress.com/?p=1383#comment-1016 最哀就係睇唔明呢句 一個電話，在空中，用手由左面移到右面，沒有workdone 最哀就係睇唔明呢句
一個電話，在空中，用手由左面移到右面，沒有workdone

]]> Comment on 跑步的物理 by KAKAKI http://pofelix.wordpress.com/2009/11/11/%e8%b7%91%e6%ad%a5%e7%9a%84%e7%89%a9%e7%90%86/#comment-1015 KAKAKI Sat, 14 Nov 2009 16:40:38 +0000 http://pofelix.wordpress.com/?p=1383#comment-1015 唔好意思 依家先來回應你地 啫係咁呀 布先生其實想講佢跑步好攰 係咁多 先於直陽具佬所講的 一真都對 布先生大概都會明白 佢用嘅example 係Conservative force 佢又"以為"friction 係Conservative force 所以係呢個假設下 佢一定岩 你地其實一樣 只是前題不同 無話邊個錯 最多我錯 給你的功課 http://www.sfu.ca/~mxchen/phys1010901/LectureCh08.pdf 唔好意思
依家先來回應你地
啫係咁呀

布先生其實想講佢跑步好攰
係咁多

先於直陽具佬所講的
一真都對
布先生大概都會明白

佢用嘅example 係Conservative force
佢又”以為”friction 係Conservative force
所以係呢個假設下
佢一定岩

你地其實一樣
只是前題不同
無話邊個錯
最多我錯

給你的功課
http://www.sfu.ca/~mxchen/phys1010901/LectureCh08.pdf

]]> Comment on 跑步的物理 by 直陽具佬 http://pofelix.wordpress.com/2009/11/11/%e8%b7%91%e6%ad%a5%e7%9a%84%e7%89%a9%e7%90%86/#comment-1014 直陽具佬 Sat, 14 Nov 2009 09:51:18 +0000 http://pofelix.wordpress.com/?p=1383#comment-1014 你真係以為 "F係mg,向下的 s係displacement,向右的 兩個vector perpenticular 所以E=Fs=0" 岩? 果段路無Netforce, F=0 s都係無,因為果段唔係 E=FS裡面既displacement 無f無e,同energy都無關,點解用e=fs諗? 真ga,如果你係一架車呢? 假設你無手無腳先 當R=1N 你1kg 你想第一秒1m/s 你用F=2N 1秒啦,你先前果個force令你而家1m/s行 你想保持時速1m/s 但R依然=1N 你要用番F=1N對抗 令Net force = 0 繼續lor wor 死啦,R仲係等於1N呀 我唔用F得唔得呀 唔好意思,你停低左 完 你真係以為
“F係mg,向下的
s係displacement,向右的
兩個vector perpenticular
所以E=Fs=0″
岩?

果段路無Netforce, F=0
s都係無,因為果段唔係 E=FS裡面既displacement

無f無e,同energy都無關,點解用e=fs諗?

真ga,如果你係一架車呢?
假設你無手無腳先
當R=1N
你1kg
你想第一秒1m/s
你用F=2N

1秒啦,你先前果個force令你而家1m/s行
你想保持時速1m/s
但R依然=1N
你要用番F=1N對抗
令Net force = 0

繼續lor wor
死啦,R仲係等於1N呀
我唔用F得唔得呀
唔好意思,你停低左

完

]]> Comment on 跑步的物理 by pofelix http://pofelix.wordpress.com/2009/11/11/%e8%b7%91%e6%ad%a5%e7%9a%84%e7%89%a9%e7%90%86/#comment-1013 pofelix Sat, 14 Nov 2009 09:18:22 +0000 http://pofelix.wordpress.com/?p=1383#comment-1013 照我理解 你一路都唔明我想講成個運動ge邊個部份 不過我明你講乜 基本上我地都啱 不過你講ge野多過我 . 之不過 跑步之所以好攰 唔係因為我地向前跑的力攰 係啱ge d力係用晒係加速同減速d手腳 同我地個身體有冇向前移動冇關 譬如: 踩住花生滑原地跑一個鐘, 同係海傍跑一個鐘, 都一樣咁攰 照我理解
你一路都唔明我想講成個運動ge邊個部份
不過我明你講乜
基本上我地都啱
不過你講ge野多過我
.
之不過
跑步之所以好攰
唔係因為我地向前跑的力攰
係啱ge
d力係用晒係加速同減速d手腳
同我地個身體有冇向前移動冇關
譬如: 踩住花生滑原地跑一個鐘, 同係海傍跑一個鐘, 都一樣咁攰

]]> Comment on 跑步的物理 by 直陽具佬 http://pofelix.wordpress.com/2009/11/11/%e8%b7%91%e6%ad%a5%e7%9a%84%e7%89%a9%e7%90%86/#comment-1012 直陽具佬 Sat, 14 Nov 2009 05:38:17 +0000 http://pofelix.wordpress.com/?p=1383#comment-1012 個外力係有意義ga 無外力既話個電話同靜止一樣 點用到你個e=fs????????? 請溫習displacement定義 Displacement (vector), in Newtonian mechanics, specifies the change in position of a point in reference to a previous position. In simple terms, it's the difference between the initial position and the final position of an object 你個理想電話，俾手推 initial position 同 final position係邊度? W = F * d If the resultant force F on an object acts WHILE the object is displaced a distance d, and the force and displacement act parallel to each other, the mechanical work done on the object is the product of F multiplied by d: W = F * d initial position係用force果點，force完, displacement完,之後果個唔係displacement kakaki，我岩唔岩? 個外力係有意義ga

無外力既話個電話同靜止一樣
點用到你個e=fs?????????

請溫習displacement定義

Displacement (vector), in Newtonian mechanics, specifies the change in position of a point in reference to a previous position. In simple terms, it’s the difference between the initial position and the final position of an object

你個理想電話，俾手推
initial position 同 final position係邊度?

W = F * d

If the resultant force F on an object acts WHILE the object is displaced a distance d, and the force and displacement act parallel to each other, the mechanical work done on the object is the product of F multiplied by d:
W = F * d

initial position係用force果點，force完, displacement完,之後果個唔係displacement

kakaki，我岩唔岩?

]]> Comment on 跑步的物理 by 真陽具佬 http://pofelix.wordpress.com/2009/11/11/%e8%b7%91%e6%ad%a5%e7%9a%84%e7%89%a9%e7%90%86/#comment-1011 真陽具佬 Sat, 14 Nov 2009 05:17:05 +0000 http://pofelix.wordpress.com/?p=1383#comment-1011 牛頓物理,constant v既野同靜止既野係一樣gor lor 咁work咩done呢? 牛頓物理,constant v既野同靜止既野係一樣gor lor

咁work咩done呢?

]]> Comment on 跑步的物理 by 真陽具佬 http://pofelix.wordpress.com/2009/11/11/%e8%b7%91%e6%ad%a5%e7%9a%84%e7%89%a9%e7%90%86/#comment-1010 真陽具佬 Sat, 14 Nov 2009 05:11:48 +0000 http://pofelix.wordpress.com/?p=1383#comment-1010 其實你講果個displacement同 e=fs一d關係都無 其實你講果個displacement同 e=fs一d關係都無

]]> Comment on 跑步的物理 by 真陽具佬 http://pofelix.wordpress.com/2009/11/11/%e8%b7%91%e6%ad%a5%e7%9a%84%e7%89%a9%e7%90%86/#comment-1009 真陽具佬 Sat, 14 Nov 2009 02:37:40 +0000 http://pofelix.wordpress.com/?p=1383#comment-1009 無漏野點會以為你跑步之所以好攰 唔係因為我地向前跑的力攰? 海旁好理想? 同埋點解你會知理想國中如果空中有個電話俾你一推,佢會displace幾遠? 佢都唔會停 隻手唔係無中生有ga? 無漏野點會以為你跑步之所以好攰
唔係因為我地向前跑的力攰?

海旁好理想?

同埋點解你會知理想國中如果空中有個電話俾你一推,佢會displace幾遠?
佢都唔會停
隻手唔係無中生有ga?

]]> Comment on 跑步的物理 by pofelix http://pofelix.wordpress.com/2009/11/11/%e8%b7%91%e6%ad%a5%e7%9a%84%e7%89%a9%e7%90%86/#comment-1008 pofelix Sat, 14 Nov 2009 00:01:38 +0000 http://pofelix.wordpress.com/?p=1383#comment-1008 我係講緊牛頓物理 同 e=fs 係理想ge condition丫嘛 除佐 地球係圓 空氣有阻力 頭果下有F 我冇咩物理知識漏佐咋話? 我係講緊牛頓物理 同 e=fs
係理想ge condition丫嘛
除佐 地球係圓 空氣有阻力 頭果下有F
我冇咩物理知識漏佐咋話?

]]> Comment on 跑步的物理 by 真陽具佬 http://pofelix.wordpress.com/2009/11/11/%e8%b7%91%e6%ad%a5%e7%9a%84%e7%89%a9%e7%90%86/#comment-1007 真陽具佬 Fri, 13 Nov 2009 17:30:09 +0000 http://pofelix.wordpress.com/?p=1383#comment-1007 都好wor 直好似好過真 有力d 都好wor
直好似好過真
有力d

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