math
posted by kat .
You are standing on a bridge over a creek, holding a stone 20 feet above the water.
1. You release the stone. How long will it take the stone to hit the water?
2. You take another stone and toss it straight up with an initial velocity of 30 feet per second. How long will it take the stone to hit the water?
3. If you throw a stone straight up into the air with an initial velocity of 50 feet per second, could the stone reach a height of 60 feet above the water?

d = Vi*t + (1/2)a*t^2
In this case, acceleration is equal to 32 ft/s/s, and the displacement is 20 ft. Vi is initial velocity.