SOLUTION: A catapult launches its ammo across a battlefield. The Height of the rock launched at any time after it has been “fired” can be found using the equation h(t)=48t-16t^2 determ

Algebra ->  Sequences-and-series -> SOLUTION: A catapult launches its ammo across a battlefield. The Height of the rock launched at any time after it has been “fired” can be found using the equation h(t)=48t-16t^2 determ      Log On


   

Question 1073859: A catapult launches its ammo across a battlefield. The Height of the rock launched at
any time after it has been “fired” can be found using the equation h(t)=48t-16t^2
determine how long itll take the rock to reach 36 feet
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+h%28t%29+=+36+
+36+=+48t+-+16t%5E2+
+9+=+12t+-+4t%5E2+
+-4t%5E2+%2B+12t+-+9+=+0+
+t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
+a+=+-4+
+b+=+12+
+c+=+-9+
+t+=+%28+-12+%2B-+sqrt%28+12%5E2-4%2A%28-4%29%2A%28-9%29+%29%29%2F%282%2A%28-4%29%29+
+t+=+%28+-12+%2B-+sqrt%28+144+-+144+%29%29%2F%282%2A%28-4%29%29+
+t+=+%28+-12+%29+%2F+%28-8%29+
+t+=+3%2F2+
It takes 1.5 sec to reach height of 36 ft and that
must be the maximum, since there is only 1 answer
Otherwise, you would get 2 answers: one for when
it was going up, and one for when it was going down.
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Here's the plot:
+graph%28+400%2C+400%2C+-1%2C+4%2C+-5%2C+50%2C+-16x%5E2+%2B+48x+%29+