SOLUTION: A golf ball is hit into the air. The path of the ball can be described by the equation h=70t-5t(squared) where h is the height of the ball in meters and t is the time in seconds.

Algebra ->  Algebra  -> Quadratic Equations and Parabolas  -> Quadratic Equation Customizable Word Problems -> SOLUTION: A golf ball is hit into the air. The path of the ball can be described by the equation h=70t-5t(squared) where h is the height of the ball in meters and t is the time in seconds.       Log On

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Question 38318: A golf ball is hit into the air. The path of the ball can be described by the equation h=70t-5t(squared) where h is the height of the ball in meters and t is the time in seconds.
A. how high is the ball after 3 seconds
B. after how many seconds will the ball be 169 meters high
C. when will the ball hit the ground?
~Thanx,
Steve
Answer by Nate(3500) About Me  (Show Source):
You can put this solution on YOUR website!
A. how high is the ball after 3 seconds
h=70%283%29-5%283%29%5E2
h=210-45
h=165
B. after how many seconds will the ball be 169 meters high
169=70%28t%29-5%28t%29%5E2
-5%28t%29%5E2%2B70t-169=0
't' is either %28-70+%2B+%281520%29%5E%281%2F2%29%29%2F%28-10%29%29 or %28-70+-+%281520%29%5E%281%2F2%29%29%2F%28-10%29%29
The answer is %28-70+-+%281520%29%5E%281%2F2%29%29%2F%28-10%29%29 because you can not have a negative time. The answer is about 10.8987
C. when will the ball hit the ground?
0=70%28t%29-5%28t%29%5E2
0=t%2870-5t%29
set to zero (use product property)
t=0
70-5t=0
-5t=-70
t=14
The ball will hit the ground after 14 seconds.