Apunter kicks a football upward with an initial velocity of 48 feet per second. after how many seconds does the ball hit the ground? use the formula h=rt−16t2, where h represents height in feet and r represents the initial velocity (rate) in feet per second. a. 456 b. 791 c. 1111 d. 1863

3 seconds

For the given problem conditions, the parameters in your formula are ...

... h = 0

... r = 48

Putting these values into the equation, we can solve for t.

... 0 = 48t -16t²

... 0 = 16t(3 -t) . . . . . factored

This will be true for t=0 and for t=3

The ball will hit the ground after 3 seconds.

Comment on answer choices

For the ball to take 456 seconds (more than 7 1/2 hours) to hit the ground, it would have to  be launched at 7296 ft/s, several times the speed of sound. Its maximum height would be over 157.5 miles, and all of the usual assumptions about a stationary flat Earth with a uniform gravity field and no air resistance could not apply.

So, we know that 456 seconds is an impossible choice (as are the higher values, such as 1863 seconds). Perhaps that should be 4 5/6 seconds. For that to be the answer, the launch speed would need to be 77 1/3 ft/s, not 48 ft/s.

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If these are the actual answer choices associated with this problem, it would be a good idea to have your teacher show you how to work it.

see explanation

step-by-step explanation:

a

(6r + 7) + (13 + 7r) ( remove brackets and collect like terms )

= 6r + 7 + 13 + 7r

= 13r + 20

b

remove brackets and collect like terms

13 - r - 1 + r

= 12 - r

c

remove brackets and collect like terms

= - 8 - r + 2r - 4

= - 12 + r

d

remove brackets and collect like terms

= 7r - - - 6r

[-   - = - - = - ]

= r -