You throw a ball at a height of 5 feet above the ground. The height h (in feet)
of the ball after t seconds can be modeled by the equation h=-16tsqaured +44t +5
A. After how many seconds does the ball reach a height of 15 feet?
B. After how many seconds does the ball hit the ground? Round your answer
to two decimal places.

Respuesta :

Answer:

A.    After 2.5 sec and .25 sec the ball was at a height of 15 ft.

B.    2.86 sec is the time it takes to hit the ground

Step-by-step explanation:

A.   let h = 15

then 15 = -16t^2 + 44t + 5

16t^2 - 44t + 10 =0

2(8t^2 - 22t + 5) = 0

2(2t - 5)(4t - 1) = 0

t = 5/2 = 2.5    or t = 1/4 = .25

After 2.5 sec and .25 sec the ball was at a height of 15 ft.

B.   Let h = 0.  

-16t^2 + 44t + 5 = 0

Use the quadratic formula to find t.  (I will let you do that)

t = 2.85929...    or t = -.10929...

t cannot be negative, so 2.86 sec is the time it takes to hit the ground

The answer of A is  After 2.5 sec and 0.25 sec the ball was at a height of 15 ft and the answer of B is 2.86 sec is the time it takes to hit the ground.

A.   let h = 15

What is the quadratic equation?

[tex]ax^2+bx+c=0[/tex]

a, b, c = known numbers, where a ≠ 0

x = the unknown

then 15 = -16t^2 + 44t + 5

16t^2 - 44t + 10 =0

2(8t^2 - 22t + 5) = 0

2(2t - 5)(4t - 1) = 0

t = 5/2 = 2.5    or t = 1/4 = 0.25

After 2.5 sec and 0.25 sec the ball was at a height of 15 ft.

B.   Let h = 0.  

-16t^2 + 44t + 5 = 0

Use the quadratic formula to find t.

t = 2.85929...    or t = -.10929...

t cannot be negative, So 2.86 sec is the time it takes to hit the ground.

To learn more about the quadratic equation visit:

https://brainly.com/question/1214333

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