Home > A2C > Chapter 11 > Lesson 11.2.4 > Problem 11-94
11-94.
For an object shot into the air, its height
For what times is the object on the ground?
Substitute 0 for h.
80t − 16t2 = 0
It is on the ground at 0 and 5 seconds.
Factor the equation.
16t(5 − t) = 0
For what domain is this function reasonable?
When is the height positive?
D: 0 ≤ t ≤ 5
How long did it take the object to hit the ground?
At what time will the object be on the ground, not including when it starts?
5 seconds
For what times is the height greater than
feet?
Substitute 64 for h and solve for t.
Factor the equation.
Simplify.
Solve for t.
Use these values to find height greater that 64 ft.