# physics

A stone is dropped from a 100m bridge. How long does it take the rock to reach the ground?

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1. Vertical Going down postive
d=100m
a=+9.8m/s2
V1=0

Use the formula
d=v1t=1/2 a t*2
100= 1/2 (9,8) t*2
100=4.9t*2
Divide 4.9 from both sides
20.4=t*2
square root 20.4
t=4.51s

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