Question 825435:  Michael throws a baseball into the air with an initial vertical velocity of 180 feet per second from a 100 foot cliff.
 
A: Write the height of the baseball as a function of time. 
B: When will the baseball be 200 feet high?  
C: When will the baseball reach its maximum height? 
D: How high is the baseball after 3 seconds? 
 Answer by TimothyLamb(4379)      (Show Source): 
You can  put this solution on YOUR website! --- 
equation of ballistic motion: 
y(t) = (1/2)gt^2 + v0t + y0 
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where y(t) is height at time t 
g = acceleration due to gravity 
v0 = initial velocity 
y0 = initial height 
t = time 
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y(t) = (1/2)-32t^2 + 180t + 100 
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answer A: 
y(t) = -16t^2 + 180t + 100 
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setup for B: 
200 = -16t^2 + 180t + 100 
-16t^2 + 180t - 100 = 0 
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the above quadratic equation is in standard form, with a=-16, b=180, and c=-100 
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to solve the quadratic equation, by using the quadratic formula, copy and paste this: 
-16 180 -100 
into this solver: https://sooeet.com/math/quadratic-equation-solver.php 
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the quadratic has two real roots at: 
t = 0.586088907 
t = 10.6639111 
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the quadratic vertex is a maximum at: ( t= 5.625, y(t)= 406.25 ) 
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answer B: 
the ball is at 200 feet twice: 
t = 0.586088907 seconds 
t = 10.6639111 seconds 
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answer C: 
at t= 5.625 seconds the ball reaches its maximum height of 406.25 feet 
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answer D: 
y(3) = -16*3^2 + 180*3 + 100 
y(3) = 496 feet 
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--- 
Solve quadratic equations, quadratic formula: 
https://sooeet.com/math/quadratic-formula-solver.php 
--- 
Solve systems of linear equations up to 4-equations 4-variables: 
https://sooeet.com/math/system-of-linear-equations-solver.php 
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