chem請教,唔識解釋(請Zend同Chem神入來)

piyopiyo

In a simple pendulum experiment,the measured length of the string was 92.4 cm by a metre ruler.The measured diameter of the bob was 3.12cm by a vernier caliper.The time for 20 oscillations was measured to be 36.0 seconds.
a.find the effective length of the pendulum[[tk_30]]wat is effective length

仲有我完全唔知幾時take幾多sig fig[[tk_30]]
有時本書計% error會take到 2sf ,但有時只係1 sf[[tk_30]]

[ 本帖最後由 piyopiyo 於 10-8-2008 10:13 編輯 ]

博士．Dota

原帖由 piyopiyo 於 10-8-2008 10:10 發表
In a simple pendulum experiment,the measured length of the string was 92.4 cm by a metre ruler.The measured diameter of the bob was 3.12cm by a vernier caliper.The time for 20 oscillations was measure ...

>a.find the effective length of the pendulum[[tk_30]]wat is effective length
應該係由ｄ實驗數據同埋論，計番條繩幾長。

piyopiyo

原帖由 博士．Dota 於 10-8-2008 13:23 發表


>a.find the effective length of the pendulum[[tk_30]]wat is effective length
應該係由ｄ實驗數據同埋論，計番條繩幾長。

咁點計[[tk_30]]

博士．Dota

36/20 = T = 2 pi * 開方(L/g)
L = [36 開方 g / (2 pi * 20 )]^2 = 0.82m

piyopiyo

點解我計mole出泥個答案黎同CCLee本野差 0.0x ....
我無論將個molar mass take到邊個位都同CCLee果本野個ans有出入[[tk_02]]
呢題唔識計
find the mass of a one-trillion(1.0x10^12)atom sample of copper.
我咁計
63.5x10^12/(6.02x10^23)=1.055 x 10^-10g...錯左[[tk_24]]

[ 本帖最後由 piyopiyo 於 11-8-2008 09:03 編輯 ]

博士．Dota

原帖由 piyopiyo 於 11-8-2008 08:45 發表
點解我計mole出泥個答案黎同CCLee本野差 0.0x ....
我無論將個molar mass take到邊個位都同CCLee果本野個ans有出入[[tk_02]]
呢題唔識計
find the mass of a one-trillion(1.0x10^12)atom sample of copper.
我咁 ...

計法無錯，不能假設答案絕對正確。

[ 本帖最後由 博士．Dota 於 11-8-2008 17:02 編輯 ]

HKwww

CCLEE本CHEM不嬲都一舊舊膠
只要你計法冇錯就OK

j32738

這兒又變了吹水帖..

piyopiyo

原帖由 HKwww 於 11-8-2008 20:04 發表
CCLEE本CHEM不嬲都一舊舊膠
只要你計法冇錯就OK

[[tk_30]]但CCLEE唔係話係AL最好ge chem書咩

piyopiyo

原帖由 j32738 於 11-8-2008 20:17 發表
這兒又變了吹水帖..

不想變吹水帖就在我不會去的版開帖吧[[tk_27]]