TOM throws a ball upwards.After a seconds,the height h m of the ball above the ground is given by h=8a-5(a^2)+1.5
問:when will the ball reach the ground?(corr the ans to 1 decimal place)
我吳是只要答案,都要式
math function一問(20分)
2010-09-02 5:58 am
回答 (1)
2010-09-02 6:15 am
✔ 最佳答案
When the ball reach the ground , the height = h = 0 ,0 = 8a - 5a^2 + 1.55a^2 - 8a - 1.5 = 0a = { - (- 8) +/- √ [8^2 - 4*5*(- 1.5)] } / (2*5)a = (8 +√ 94) / 10 or (8 - √ 94) / 10 (rejected)a = 1.76954The ball will reach the ground after 1.8 seconds.(1 dec.)
收錄日期: 2021-04-21 22:17:24
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100901000051KK01594