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A ball is kicked with an initial height of 0.75 meters and an initial upward velocity of 22 meters/second. This inequality represents the time, [tex]\( t \)[/tex], in seconds, when the ball's height is greater than 10 meters.

[tex]\[
-4.9 t^2 + 22 t + 0.75 \ \textgreater \ 10
\][/tex]

The ball's height is greater than 10 meters when [tex]\( t \)[/tex] is approximately between [tex]\(\square\)[/tex] and [tex]\(\square\)[/tex] seconds.


Sagot :

To determine the time intervals during which the ball's height is greater than 10 meters, we need to solve the given inequality:

[tex]\[ -4.9 t^2 + 22 t + 0.75 > 10 \][/tex]

First, let's simplify the inequality by moving the constant term from the right-hand side to the left-hand side:

[tex]\[ -4.9 t^2 + 22 t + 0.75 - 10 > 0 \][/tex]

This simplifies to:

[tex]\[ -4.9 t^2 + 22 t - 9.25 > 0 \][/tex]

Next, we need to find the values of [tex]\( t \)[/tex] that satisfy this inequality. Solving this quadratic inequality involves finding the roots of the corresponding quadratic equation:

[tex]\[ -4.9 t^2 + 22 t - 9.25 = 0 \][/tex]

Once the roots of this equation are determined, we can identify the intervals where the quadratic expression is greater than zero.

The roots of this quadratic equation are approximately:

[tex]\[ t_1 \approx 0.469563696261278 \][/tex]
[tex]\[ t_2 \approx 4.02023222210607 \][/tex]

Since the quadratic coefficient is negative (-4.9), the parabola opens downwards. Therefore, the quadratic expression is greater than zero between the roots. So, the ball's height is greater than 10 meters in the interval:

[tex]\[ 0.469563696261278 < t < 4.02023222210607 \][/tex]

Thus, the ball's height is greater than 10 meters when [tex]\( t \)[/tex] is approximately between [tex]\( 0.469563696261278 \)[/tex] and [tex]\( 4.02023222210607 \)[/tex] seconds.

In summary:
The ball's height is greater than 10 meters when [tex]\( t \)[/tex] is approximately between [tex]\(\boxed{0.469563696261278}\)[/tex] and [tex]\(\boxed{4.02023222210607}\)[/tex] seconds.