Acceleration is:
a=g
Velocity is the integral of the above
v=gt+v0
And position is the integral of the above
h=gt^2/2+v0t+h0
You are given that v0=15ft/s and h0=0ft and let g≈-32 so
h(t)=-16t^2+15t
It will hit the ground when h(t)=0 so:
0=-16t^2+15t which is equal to
16t^2-15t=0 factor
t(16t-15)=0, since we are looking for the time other than zero...
t=15/16 of a second :)
So they obviously just rounded to one whole second. So C.) was the correct answer. (Although I would say they are all wrong because they didn't SAY to round the answer :P) Haha, not trying to confuse you, the answer is most likely C. because they had the correct equation.
A
(-2c-3d) (- 11) (- 2c-3d) (- 11) left parenthesis, minus, 2, c, minus, 3, d, right parenthesis, left parenthesis, minus, 11, right parenthesis
C
(66c + 99d) \ cdot \ dfrac {1} {3} (66c + 99d) ⋅ 3
1 left parenthesis, 66, c, plus, 99, d, right parenthesis, dot, start fraction, 1, divided by, 3, end fraction
<span> E
11\cdot(2c+3d)11⋅(2c+3d)11, dot, left parenthesis, 2, c, plus, 3, d, right parenthesis
</span> answer
(-2c-3d) (- 11) = 22c + 33d
(66c + 99d) * 1/3 = 22c + 33d
11 * ( 2c+3d) = 22c + 33d
The first answer is correct, if you go back by 5% each year you will see that.