Question

After a baseball is hit, the height h (in feet) of the ball above the ground t seconds after it is hit can be approximated by the equation h = -16t² + 64t + 3. Determine how long it will take for the ball to hit the ground. Round your answer to the nearest hundredth... Please help .. It is due tomorrow

Answer 1

Answer:

The ball will take 4.05 seconds to hit the ground.

Step-by-step explanation:

we have

$h=-16t^{2}+64t+3$

This is a quadratic equation (vertical parabola) open down

The vertex is a maximum

we know that

The ball hit the ground when h=0

Solve the quadratic equation

For h=0

$-16t^{2}+64t+3=0$

The formula to solve a quadratic equation of the form

$at^{2} +bt+c=0$ is equal to

$t=\frac{-b(+/-)\sqrt{b^{2}-4ac}} {2a}$

in this problem we have

$-16t^{2}+64t+3=0$  

so

$a=-16\\b=64\\c=3$

substitute in the formula  

$t=\frac{-64(+/-)\sqrt{64^{2}-4(-16)(3)}} {2(-16)}$

$t=\frac{-64(+/-)\sqrt{4,288}} {-32}$

$t=\frac{64(-)\sqrt{4,288}} {32}=-0.05\ sec$  ---> the time cannot be a negative number

$t=\frac{64(+)\sqrt{4,288}} {32}=4.05\ sec$

therefore

The ball will take 4.05 seconds to hit the ground.