physics
posted by Natasha .
A dynamite blast at a quarry launches a chunk of rock straight upward, and 2.0s later it is rising at a speed of 15m/s. Assuming air resistance has no effect, calculate its speed A) at launch and B) 5.0s after lauch

v = Vi  9.8 t
15 = Vi  19.6
Vi = 34.6 s
so
v = 34.6  9.8 t
You can do that for t = 5
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