Quadractic Functions and Equat

Question

A smoke jumper jumps from a plane that is 1800 feet above the ground. The function h=-16t²+1800 gives the jumper's height h in feet during the free fall at t seconds.

 

a. How long is the jumper in free fall if the parachute opens at 1000 feet?

 

b. How long is the jumper in free fall if the parachute opens at 930 feet?

 

c. What is a reasonable domain and range for the function h?

Answer 1

(a)

 

Set h = 1000 and solve for t

 

1000 = -16t² + 1800

 

t² = 800/16 = 50

 

t = √50 s ≅ 7.07 s

 

(b)

 

Set h = 930 and solve for t

 

930 = -16t² + 1800

 

 

t² = 870/16

 

t = √(870/16) s ≅ 7.37 s