Your friend is standing below the window outside of our classroom and attempting to throw a rock past the window to get your attention. The rock is thrown straight up in the air and passes our window 0.40s after being released. It passes the same window on its way back down 1.60s later. What was the initial velocity of the rock? Did the height of the

Question

window matter?

Answer 1

once past the window, the rock spent .8 seconds going up and .8 seconds going down.

So, the rock spent 1.2 seconds going up.

since v = Vo-32t and v(1.2)=0,

Vo-32(1.2)=0
Vo = 38.4

Doesn't matter how high the windows is, though its location is determined by the time intervals indicated.