An arrow is shot vertically downwards, and strikes the ground at a speed of 29.2 m/s, 10.9 m below from where it was shot. With what initial speed was the arrow shot?

Explanation:

Ignoring air resistance

v² = u² + 2as

u = √(v² - 2as)

u = √(29.2² - 2(9.81)(10.9))

u = 25.27413... 25.3 m/s

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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