Question

A bird drops a stick to the ground from a height of 68ft. The function h=-16t^2+68 gives the stick's approximate height h above the ground, in feet after t seconds. At about what time does the stick hit the ground

Answer 1

The stick will hit the ground when h = 0

- 16 t² + 68 =0

Multiply both sides by - 1

16 t² - 68 =0

Add 68 to both sides

16 t² = 68

t² = 68 / 16 = 4 ∙ 17 / 4 ∙ 4 = 17 / 4

t = ± √17 / √4 = ± √17 / 2

Time can't be be negative so:

t = √17 / 2

t = 2.0615528128 sec

Answer 2

Thank you so much:)