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 left parenthesis t right parenthesis equals negative 18 t squared plus 72 t plus 378, where h is the height of the debris, in metres, and t is the time, in seconds.
How long will it take for the piece of debris to hit the ground after an explosion?
How long will it take for the piece of debris to hit the ground after an explosion?
Answers
Bosnian
h(t) = - 18 t² + 72 t + 378
The piece of debris hit the ground when h = 0
h(t) = - 18 t² + 72 t + 378 = 0
Now you must solve equation:
- 18 t² + 72 t + 378 = 0
The solutions are:
t = - 3 and t = 7
Time cannot be negative.
So t = 7 sec
The piece of debris hit the ground when h = 0
h(t) = - 18 t² + 72 t + 378 = 0
Now you must solve equation:
- 18 t² + 72 t + 378 = 0
The solutions are:
t = - 3 and t = 7
Time cannot be negative.
So t = 7 sec