An object is thrown directly downward from the top of a 180 meter tall building. It takes 1.0 seconds for the object to fall the last 60 meters. With what initial downward speed was the object thrown from the roof?
Answer Choices
A. 15 \mathrm{~m} / \mathrm{s}
B. 25 \mathrm{~m} / \mathrm{s}
C. 35 \mathrm{~m} / \mathrm{s}
D. 55 \mathrm{~m} / \mathrm{s}
E. insufficient information.