a bullet is fired vertically upwards from the ground at a speed of 350ms^-1 .
after what time will it return to the ground?
f.4 physics
2009-10-05 4:51 am
回答 (1)
2009-10-05 4:55 am
✔ 最佳答案
The speed is much lower than the escape speed of the Earth. So, it is safe to use equation of motion to tackle this problem.Let upward direction be positive.
Initial speed, u = 350 ms-1
Acceleration due to gravity, g = -10 ms-2
Displacement, s = 0
By s = ut + 1/2 gt2
0 = (350)t + 1/2 (-10)t2
Time, t = 70 s or 0 (rejected)
參考: Physics king
收錄日期: 2021-04-19 15:27:03
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