posted by JC on .
A rock is thrown vertically upward with a speed of 11.0 from the roof of a building that is 70.0 above the ground. Assume free fall.
In how many seconds after being thrown does the rock strike the ground?
What is the speed of the rock just before it strikes the ground?
The smart aleck answer is, "If it's thrown straigt up then how can it land on the ground? It should land on the roof, right?"
Ignoring that, figure out how long it will rise and what it's velocity will be when it returns to the building's height, then use that for the initial velocity if it had been thrown off the building.
Once again I see that you're not supplying units so I don't know what to make of the question.
refer to the other qs