A stone is projected vertically upwards from ground level at a speed of 24.5ms-1. Find how long after projection the stone is at a height of 19.6m above the ground:
i)for the first time
ii)for the second time
Thanks in advanced
Kinematic question?
2021-01-11 11:41 am
回答 (1)
2021-01-11 12:42 pm
✔ 最佳答案
Take g = 9.8 m/s²h = ut - (1/2)gt²
19.6 = 24.5t - (1/2)*9.8*t²
4.9t² - 24.5t + 19.6 = 0
t² - 5t + 4 = 0
(t - 1)(t - 4) = 0
t = 1 or t = 4
(i) Time taken for the first time = 1 s
(ii) Time taken for the second time = 4s
收錄日期: 2021-04-25 13:55:12
原文連結 [永久失效]:
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