SOLUTION: Each function h (t) below represents an object being thrown upward with an initial velocity after t seconds. For each function find the time that it takes to reach the ground.

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: Each function h (t) below represents an object being thrown upward with an initial velocity after t seconds. For each function find the time that it takes to reach the ground.       Log On


   

Question 999922: Each function h (t) below represents an object being thrown upward with an initial velocity after t seconds. For each function find the time that it takes to reach the ground. a)h(t)=-16t2+64t+960 b)ℎ(𝑡)= −16𝑡2 +80𝑡+576 c) ℎ(𝑡)= −16𝑡2 +64𝑡+960

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
the time that it takes to reach the ground:
a)
h%28t%29=-16t%5E2%2B64t%2B960
the object will reach the ground, when its height is zero
0=+-16t%5E2%2B64t%2B960
0=+-16%28t%5E2-4t-60%29
0=+-16%28t%5E2-10t%2B6t-60%29
0+=+-16+%28t-10%29+%28t%2B6%29
=>t=10 or t=-6+
Only the + sign makes sense. =>t=10
b)
0=+-16t%5E2+%2B80t%2B576
0=+-16%28t%5E2+-5t-36+%29
0=+-16%28t%5E2+-9t%2B4t-36+%29
0=+-16%28%28t%5E2+-9t%29%2B%284t-36+%29%29
0=+-16%28t%28t+-9%29%2B4%28t-9+%29%29
0+=+-16+%28t-9%29+%28t%2B4%29
=>t=9 or t=-4
Only the + sign makes sense. =>t=9

your function c) is same as a)