# 查看完整版本 : 從KE-T graph看acceleration

## 從KE-T graph看acceleration

sorry唔記得調反岩個方向tim:smile_43:

dustbus 2013-4-1 08:50 PM

dustbus 2013-4-1 09:04 PM

1開始KE=0,跟住仲decelerate???個唯一講法咪姐係向相反方向加速

[quote]原帖由 [i]dustbus[/i] 於 2013-4-1 21:04 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=357294657&ptid=21702601][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
1開始KE=0,跟住仲decelerate???個唯一講法咪姐係向相反方向加速 [/quote]solution：

dustbus 2013-4-1 10:31 PM

1/2mat^2=1/2mv^2
at^2=v^2

[quote]原帖由 [i]dustbus[/i] 於 2013-4-1 22:31 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=357303080&ptid=21702601][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]

1/2mat^2=1/2mv^2
at^2=v^2

[url=http://m.discuss.com.hk][img=100,23]http://i1.hk/d/images/r10/mobile.jpg[/img][/url]

14c14c 2013-4-1 10:57 PM

let k be some positive constant such that kt=K.E.
then 2kt=mv^2
2kt/m=(ds/dt)^2
sqrt(2kt/m) = ds/dt (we may choose the direction s.t. ds/dt>0)
0.5sqrt(2k/m)t^(-1/2) = ds^2/dt^2 = acceleration = a which is decreasing as t increase

14c14c 2013-4-1 10:59 PM

[quote]原帖由 [i]dustbus[/i] 於 2013-4-1 10:31 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=357303080&ptid=21702601][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]

1/2mat^2=1/2mv^2
at^2=v^2

(y=mx)

↗亢龍無悔↙ 2013-4-1 11:28 PM

[[i] 本帖最後由 ↗亢龍無悔↙ 於 2013-4-1 11:29 PM 編輯 [/i]]

14c14c 2013-4-2 12:55 AM

[quote]原帖由 [i]↗亢龍無悔↙[/i] 於 2013-4-1 11:28 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=357309234&ptid=21702601][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]

EM, wave, matter..全部死晒, 最後直頭drop埋physics:smile_27:

dustbus 2013-4-2 08:39 PM

[quote]原帖由 [i]14c14c[/i] 於 2013-4-1 10:59 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=357306182&ptid=21702601][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]

(y=mx) [/quote]

14c14c 2013-4-2 11:35 PM

[quote]原帖由 [i]dustbus[/i] 於 2013-4-2 08:39 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=357388663&ptid=21702601][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]

kt=0.5mv^2
(2k/m)t=v^2

you can see t and v^2 are linear
since k is positive constant, m is positive constant, (2k/m) is a positive constant:smile_44:

dustbus 2013-4-2 11:40 PM

:funk: :funk: :funk: thank you ching

Zzlaz 2013-4-3 08:44 PM

[quote]原帖由 [i]14c14c[/i] 於 2013-4-2 00:55 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=357317799&ptid=21702601][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]

EM, wave, matter..全部死晒, 最後直頭drop埋physics:smile_27:

Zzlaz 2013-4-11 07:47 PM

dustbus 2013-4-11 08:41 PM

pure math日常生活根本唔會用到:smile_27: :smile_27:

[quote]原帖由 [i]dustbus[/i] 於 2013-4-11 20:41 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=358219571&ptid=21702601][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
pure math日常生活根本唔會用到:smile_27: :smile_27: [/quote]dustbus師兄讀m1定m2？我m1

Zzlaz 2013-4-11 09:21 PM

[quote]原帖由 [i]dustbus[/i] 於 2013-4-11 08:41 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=358219571&ptid=21702601][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
pure math日常生活根本唔會用到:smile_27: :smile_27: [/quote]

dustbus 2013-4-11 10:01 PM

[quote]原帖由 [i]Zzlaz[/i] 於 2013-4-11 09:21 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=358223014&ptid=21702601][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]

[quote]原帖由 [i]雲艾法比[/i] 於 2013-4-11 09:16 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=358222590&ptid=21702601][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
dustbus師兄讀m1定m2？我m1 [/quote]

darigold 2013-4-25 06:15 AM

[quote]原帖由 [i]darigold[/i] 於 2013-4-25 06:15 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=359479732&ptid=21702601][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]

37182456 2013-4-28 02:31 PM

ke係0.5mv？,v二次左線性上升，姐係話vt graph個v係條curve,係increasing with a decreasing rate,所以acceleration係decreasing

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