science

A rock tumbles straight down from a cliff, its moving at 20 m/s when it hits. What is the height of the cliff? The mass of the rock is 8 kg.
a) 2.5 m
b) 400 m
C) 20.4 m
d) 160 m

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asked by katie
  1. What's the time?

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  2. v = g t
    20 = 9.81 t
    t =2.03 seconds

    h = (1/2) g t^2
    h = 4.9 (2.03)^2
    h = 20.4 meters

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    posted by Damon
  3. yolo

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    posted by yolo

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