Question

Medal and Fan
Im not very good at algebra

Arianna kicks a soccer ball off the ground and into the air with an initial velocity of 42 feet per second. Assume the starting height of the ball is 0 feet. Approximately what maximum height does the soccer ball reach?

1.3 ft
2.6 ft
26.0 ft
27.6 ft

Answer 1

@peachpi

Answer 2

Using the same H(t) formula from the last one H(t) = -16t² + vt + s, what's v and what's s?

Answer 3

v is 42 s is 0?

Answer 4

yep, so we have
H(t) = -16t² + 42t

so now we just need to find the vertex. For a quadratic function in the form
\[y=ax^2+bx+c\]
the vertex is \[\left( \frac{ -b }{ 2a },f \left( \frac{ -b }{ 2a } \right) \right)\]

We have a = -16, b = 42, and c = 0
So for the time, find \[t=\frac{ -42 }{ 2*-16 }\]
Then plug it into our function to get the max height

Answer 5

ok so it would be h(t)=-16t^2 + 42t and substitute 1.31 for t?

Answer 6

yes

Answer 7

and the answer becomes D correct?

Answer 8

yes