1. The problem statement, all variables and given/known data A ball is tossed up in the air from the top of a tower. The function for this is y = -16t2 + 64t + 80. The problems are: a) What is the velocity of the ball after 4 seconds? b) What was the initial velocity that the ball was tossed? c) When will the ball reach its maximum height? 2. Relevant equations v=v0 + at, s = v0t + at2/2 And the derivative equation CNXN-1, dx/dy 3. The attempt at a solution Well, I calculated the velocity at 1 second (a different part of the problem) and got 32 m/s. 32 is also the acceleration I got from the 2nd derivative, which doesn't make sense since shouldn't it be -9.81? I know you use the 1st deriv to find instant velocity, but how do you figure out the initial velocity? do you just use those old formulas that I listed, or do you apply calculus to this? I know how to find instant velocity using derivative, but don't know how to do velocity after a period of time (4 seconds). An part c) I have no idea.