Pekka tosses a ball out of a window that is 40 feet in the air. Its initial velocity is 15 feet per second. The path of the ball is represented by
h = -16t2 + 15t + 40
How long does it take for the ball to hit the ground (in seconds) rounded to the
nearest hundredth?

2.12 seconds

Step-by-step explanation:

Given

Required

Determine how long the ball hits the ground

When the ball hits the ground means that

So, we have that:

becomes

Reorder

Multiply through by -1

Solve using quadratic:

Where

So, we have:

becomes

Split:

or

or

or

But time can't be negative

So:

Hence, time to hit the ground is 2.12 seconds

(1,4) is on graph of f(x)

f(1) = 4

so 1/4 f(x)

1/4 f(1)

1/4. ×4

1

so point for function 1/4. f(x) is (1,1)