Question
An explosives company specializes in bringing down old buildings. The time it takes for a particular piece of flying debris to fall to the ground can be modelled by the function h(t)= -12(t+2)^2 + 120(t+2), where h is the height of the debris in metres and t is the time in seconds.
1.) How long will it take for the piece of debris to hit the ground after an explosion? Show all work
1.) How long will it take for the piece of debris to hit the ground after an explosion? Show all work
Answers
Steve
it hits the ground when h=0. So, just solve
-12(t+2)^2 + 120(t+2) = 0
or, if you prefer
t^2-6t-16 = 0
-12(t+2)^2 + 120(t+2) = 0
or, if you prefer
t^2-6t-16 = 0