# physics

An object is dropped from a height H. During the final second of its fall, it traverses a distance of 57.8 m. What was H?

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1. you have posted three of these motion problems without any demonstrated effort. We will be happy to critique your efforts.

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bobpursley
2. h positive up
h(t) = Hi + Vi t -4.9 t^2
0 = 57.8 + Vi*1-4.9*1^2
Vi = -52.9 m/s at 57.8 m
so how far did it fall to get to that speed and height?
v = -gt
-52.9 = -9.8 t
t = 5.40 seconds
how far did it fall in those first 5.4 seconds? 4.9 * 5.4^2
57.8 = Hi - 4.9 * 5.4^2
Hi = 143 + 58 = 201 m

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