A smart-phone is thrown upwards from the top of a 240-foot building with an initial velocity of 32

feet per second. The height h of the smart-phone after t seconds is given by the quadratic equation

h = - 16t2 + 32t + 240. When will the smart-phone hit the ground?

Question

Bennett Wu

Mathematics

14 May, 04:54

A smart-phone is thrown upwards from the top of a 240-foot building with an initial velocity of 32

feet per second. The height h of the smart-phone after t seconds is given by the quadratic equation

h = - 16t2 + 32t + 240. When will the smart-phone hit the ground?

+3

Answers (1)

Know the Answer?

Rhett Aguirre · Answer 1

t = 5 sec

Step-by-step explanation:

h = - 16t² + 32t + 240

On the ground h = 0.

- 16t² + 32t + 240 = 0 / : ( - 16)

t² - 2t - 15 = 0

(t-5) (t+3) = 0

t = 5, t = - 3

Time can be only positive, so t = 5 sec

A smart-phone is thrown upwards from the top of a 240-foot building with an initial velocity of 32feet per second. The height h of the smart-phone after t seconds is given by the quadratic equationh = - 16t2 + 32t + 240. When will the smart-phone hit the ground?

A smart-phone is thrown upwards from the top of a 240-foot building with an initial velocity of 32

feet per second. The height h of the smart-phone after t seconds is given by the quadratic equation

h = - 16t2 + 32t + 240. When will the smart-phone hit the ground?