The value of t at a height of 11 feet is 0.36 sec when the ball is going upwards and 1.39 seconds when the ball is coming downwards.
A quadratic equation is an equation whose leading coefficient is of second degree also the equation has only one unknown while it has 3 unknown numbers.
It is written in the form of ax²+bx+c.
Given that the height of the ball at time t is given by the function,
[tex]h(t) = 3+ 28t -16t^2[/tex]
where t is in seconds and h is in feet.
Now, the height of the ball is given to be 11 feet, therefore, substituting the value of h in the function as 11,
[tex]h(t) = 3+ 28t -16t^2\\\\11 = 3+ 28t -16t^2\\\\-16t^2 + 28t +3 -11 = 0\\\\-16t^2 + 28t -8 = 0[/tex]
Now, solving the given quadratic equation, we will get,
[tex]x= \dfrac{-b\pm \sqrt{b^2-4ac}}{2a}\\\\t = \dfrac{-(28)\pm \sqrt{(28)^2-4(-16)(-8)}}{2(-16)}\\\\t= 0.36\ or\ 1.39[/tex]
Hence, the value of t at a height of 11 feet is 0.36 sec when the ball is going upwards and 1.39 seconds when the ball is coming downwards.
Learn more about Quadratic Equations:
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