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Home > PC > Chapter 11 > Lesson 11.1.2 > Problem 11-31


A water balloon is tossed from the top of a walkway so that its height above the ground is found by h(t) = −16t2 + 20t + 50 where h is measured in feet and t is measured in seconds. Approximate the instantaneous velocity of the water balloon when it strikes the ground. Homework Help ✎

First determine when the ball hits the ground, or when h(t) = 0.

The ball hits the ground when t = 2.5 seconds.

The velocity is the instantaneous rate of change (IROC). See the Math Notes box in Lesson 9.2.1 for the formula.