[phy]今年A-level 的試題

dolphin_ice · 發表於 18/6/2007 12:09 AM

之其中一條
大家估下la...

1. Give a situation of the following:

a) The acceleration is in 90degree angle to the motion

b) The object is stationary, but accelerating

c) The resultant force is 0, but the object is moving

abc666 · 發表於 18/6/2007 09:17 AM

b)設一物件向前行的速度是正,該物件一開始向後移動,然後向前加速,速度由負數到正數中經過速度是0的一瞬間,該物件是不動的,但在加速中
Let the speed of he object when moving backward be negative. At the begining, the object is moving backward. then it accelerate forward.when the speed of the object changes from negative to positive, it pass through a point that the speed is 0. At that time, the object is stationary, but accelerating.

sapphire · 發表於 18/6/2007 10:09 AM

比起HKALE實在是不夠看orz

a) Consider an object moving in a circular path. Its acceleration is always towards the centre of the path, and its direction of motion is tangential to the circular path. So its acceleration is always perpendicular to its direction of motion.

c) Consider a rod resting on a table. Then two forces, equal in magnitude but opposite in direction, are acted on the two ends of the rod, in the direction perpendicular to it. The resultant force acting on the rod is zero, but there is a torque causing the rod to have a turning motion.

[ 本帖最後由 sapphire 於 18/6/2007 16:33 編輯 ]

dolphin_ice · 發表於 19/6/2007 11:51 PM

咦? 掂喎, 你2個.
*拍手*

fish · 發表於 20/6/2007 06:38 AM

原帖由 dolphin_ice 於 19/6/2007 08:51 發表

 登錄/註冊後可看大圖

咦? 掂喎, 你2個.
*拍手*

abc666是F5的~
(逃~~

sapphire · 發表於 20/6/2007 10:27 AM

原帖由 dolphin_ice 於 19/6/2007 23:51 發表

 登錄/註冊後可看大圖

咦? 掂喎, 你2個.
*拍手*

這些只是mechanics的basic concept......

原帖由 fish 於 20/6/2007 06:38 發表

 登錄/註冊後可看大圖

abc666是F5的~
(逃~~

b和c也是CE生會的題目,其實還有幾個example的

[ 本帖最後由 sapphire 於 20/6/2007 10:30 編輯 ]

abc666 · 發表於 20/6/2007 11:12 AM

我記得a上堂有教過的但忘記了~.~

STEVE · 發表於 21/6/2007 12:12 PM

c: an object falling with terminal velocity 計不計?

水龍蜥 · 發表於 21/6/2007 05:56 PM

看完有關resultant force既資料...

登錄/註冊後可看大圖

對呢一個唔係好明下...

abc666 · 發表於 21/6/2007 06:09 PM

有冇學過vector?

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