Question

If a football player passes a football from 4 feet off the ground with an initial velocity of 36 feet per second, how long will it take the football to hit the ground? Use the equation h = -16t2 + 36t + 4.

A) quantity of 9 plus or minus square root of 65 all over 8
B) 9 plus or minus square root of 65 end root over 8
C) quantity of 9 plus or minus square root of 97 all over 8
D) 9 plus or minus square root of 97 end root over 8

Answer 1

Perhaps I'm wrong, but to solve this problem why don't you just set h=0 and solve this quadratic using the quadratic formula? We know that at t=0 that h=4 because you can just look at the equation and tell that when you plug in 0 for t, h=4. So we know that if we use the quadratic formula you'll get two answers, but one of them will be a negative time which doesn't make sense for a physics problem thus can be ignored. So the correct solution would be the number that is positive when you use the quadratic formula.

Answer 2

Maybe this will make it easier to see the answers

Answer 3

Do you think its A, B, C, or D

Answer 4

Let me to do the calculation and see, hold on.

Answer 5

Okay

What do you think the correct answer is? I know which one it is.

Answer 6

C or D

Answer 7

but leaning more towards D

Answer 8

The right answer is C.

Answer 9

oh ok thank you!!