- #1
Ab17
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Homework Statement
A stone is dropped from rest from the roof of a 100-m high building; 2.00 s after that, a second stone is thrown straight down with initial speed v0, and the second stone passes the first stone 21.6 m above ground. (a) When are the stones at the same height? (b) What was the initial speed, v0, of the second stone, in m/s? (c) What are the speeds of the two stones, in m/s, just before they hit the ground?
h= 100m
h(meet)= 26.1m
V1i= 0m/s
Homework Equations
Xf=Xi +Vt +0.5at^2
The Attempt at a Solution
(a). Xf1= -4.9t^2
Xf2 = Vo(t-2) -4.9(t-2)^2
-73.1 = -4.9t^2
(b). -73.1 = Vo(1.86) -4.9(1.86)^2
Vo = 30.19 m/s
(c). Vf = Vi + at
Vf = 0 -9.8(3.86)
Vf = 37.83 m/s
Vf= 30.19 -9.8(1.86)
Vf= 48.42m/s
Am I right? Not sure if I am