下圖(網址)顯示某物體的力-時間關係線圖，物體的質量是5kg。
http://file.qooza.hk/userfile/4/4/93244/ph1.JPG
a)物體正進行甚麼運動?以勻速運動、越走越快、越走越慢、還是靜止不動?試扼要解釋。
中四物理...(急...明天交)
2008-01-25 5:13 am
回答 (2)
2008-01-25 5:40 am
✔ 最佳答案
這物體在不同時段作不同的運動:因F=ma=5a,
在首5s,f=0,即a=0, 物體是靜態或勻速運動.
在5-10s,f=20,即a=4,物體是加速,
在10-20s,f=5,即a=1,物體仍然是加速,但加速得比較小.
在20-30s,f=0,即a=0,物體是以第10s時的速度作勻速運動或靜止不動.
2008-01-25 5:41 am
F = ma
m is a positve constant => F increase -> a increase, vise versa
0-5s, F = 0 => a = 0
uniform motion
5-10s, F > 0 => a > 0
acceleration
10-20s, F > 0 => a > 0
acceleration (smaller than the one within 10-15s because F is smaller)
20-25s, F = 0 => a = 0
uniform motion
m is a positve constant => F increase -> a increase, vise versa
0-5s, F = 0 => a = 0
uniform motion
5-10s, F > 0 => a > 0
acceleration
10-20s, F > 0 => a > 0
acceleration (smaller than the one within 10-15s because F is smaller)
20-25s, F = 0 => a = 0
uniform motion
收錄日期: 2021-04-13 15:01:14
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080124000051KK03316