SOLUTION: can you help me solve these problem? An arrow is shot into the air with an upward velocity of 48 ft.per second from a hill 32 ft high.The height h of the arrow can be found using

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: can you help me solve these problem? An arrow is shot into the air with an upward velocity of 48 ft.per second from a hill 32 ft high.The height h of the arrow can be found using       Log On


   

Question 195469: can you help me solve these problem?
An arrow is shot into the air with an upward velocity of 48 ft.per second from a hill 32 ft high.The height h of the arrow can be found using the model h=32 +48t -16t^ where t is the time in seconds.How many seconds after release will the arrow be 64 ft. above the ground?I will appreciate very much if you can help me.
Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
h=32+%2B48t+-16t%5E2
At what time is the height 64?
64+=+32+%2B48t+-16t%5E2
0+=+-16t%5E2+%2B+48t+-+32
0+=+t%5E2+-3t+%2B+2
0+=+%28t-2%29%28t-1%29
t = 1 and t =2
It is at 64 feet in two places. First at 1 second in, then again at 2 seconds.
Here is the graph of the arc. Note that the part of the graph to left of time=0, does not apply.
graph%28400%2C400%2C-1%2C4%2C-10%2C90%2C-16x%5E2+%2B+48x+%2B+32%29