Item 14 Question 1 An object falls 16t2 feet in t seconds. You drop a rock from a bridge that is 75 feet above the water. Will the rock hit the water in 2 seconds?

Question

In 2 seconds the rock has fallen _____ feet.

Therefore, the rock will or will not hit the water in two seconds.

Answer 1

16(2)^2 = 16(4) = 64 feet < 72 feet, so after 2 seconds, the rock will be 8 feet short of reaching the water

72 =16t^2

t^2 = 72/16 = 4.5

t = sqr4.5 = about 2.12 seconds to hit the water