Question

#13 how many seconds will it take for a ball dropped from a window 144 feet high to hit the ground below?

Answer 1

Question 13.

Given:

Height = 144 feet.

Let's determine how many seconds it will take for a ball dropped from a window of the given height to hit the ground.

Here, we have the equation:

`y=-16x^2+144`

Where:

y represents the height of the ball after x seconds.

Now, when the ball hits the ground, the height will be 0 ft.

Thus, to find the time at 0 ft, substitute 0 for y and solve for x:

`\begin{gathered} 0=-16x^2+144 \\ \\ 16x^2=144 \end{gathered}`

Divide both sides by 16:

`\begin{gathered} (16x^2)/(16)=(144)/(16) \\ \\ x^2=9 \end{gathered}`

Take the square root of both sides:

`\begin{gathered} √(x^2)=√(9) \\ \\ x=3 \end{gathered}`

Therefore, it will take the ball 3 seconds to hit the ground.

ANSWER:

• (a). y = -16t² + 144

• (b). 3 seconds