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力學有什麼重要點??力學好難呀...溫時很容易混淆d概念...力學有什麼重要點??
5該,,,teach me..

2007-03-21 09:41:36 · 2 個解答 · 發問者 ka yan 1 in 科學 其他:科學

2 個解答

最重要在於,畫圖講故事。
做每一題都要認真畫圖:
eg:       a->   
   0m/s       20m/s  
  o--->      o--->
  {------50m------}
          4s


free body diagram都唔好懶,要認真諗清楚。
唔好死背公式,要真係明。

溫的重點在於:
3(4)基公運動學公式。
newton's second law (note:係net force=ma,唔係F=ma!)
energy--->net forec x distance
   --->p.e=mgh
   --->k.e=1/2mv^2
power=energy/time taken
momentum=mv
momentum change=mv-mu
impulssive force=ma
       =m(v-u)/t
       =momentum change/time
conservation of momentum
conservation of energy

phy唔係一科記野ge科,要考更好一定要明,所有公式都只係工具。唔明一定要問!

希望幫到你^^

2007-03-21 15:11:37 · answer #1 · answered by chan 2 · 0 0

There are only three important equations:

1. impulse = change of momentum
2. work done = change of kinetic energy
3. force = mass x acceleration

togethr with the two conservation laws (conservation of energy and conservation of momentum), you could solve over 90% of the calculation problems.

2007-03-21 09:51:12 · answer #2 · answered by 天同 7 · 0 0

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