. You will be concentrating your work in the vicinity of t = 3 seconds. Drop the Ball - Height vs Time 50 10 30 height (feet) 20 10 0) OL -10 19 2.0 2.2 2.4 2.6 2.8 3.0 3.2 time (sec) . It may be more convienient to allow At take on negative values as you approach t = 3 from the left hand side. (That is, you might look at At = -1, -.5, -.1, -.01, the corresponding t values are then: t =2, 2.5, 2.9, 2.99 seconds) . You may want to use the following table to set up the problem: t At t+At S (t+At) s (t) s (3+At)-s (3) s (3+At)-s (3) / At 3 -1 2 s (2) =48 s (3) =0 48 48 3 -0.5 2.5 s (2.5)=28 s (3) =0 28 56 3 -0.1 2.9 s(2.9)=?? s(3)=0 3 -0.01 2.99 s (2. 99)=?? s (3)=0