quadratics

[serene gazelle]

I know t stands for time, but how do you solve for h when you don't have a value for t? Am I missing something?

[jade creek]

@royal leaf I'm assuming you're asking about what to do for 8b?

The time the ball was hit is the same as t=0. You should be able to compute the rest

[serene gazelle]

Doesn't that mean that the ball has no height when t=0?

[jade creek]

No. When t = 0, we just know that the time is equal to 0. To figure out the height at that time, we need to plug t = 0 into the height equation, $h = -2.1(t-2.4)^2 + 13$.

[zenith sedge]

starhands

[jade creek]

The quadratic is in vertex form. Vertex form is given by $y = a(x-h)^2 + k$, where $h$ is the $x$ coordinate of the vertex and $k$ is the $y$ coordinate of the vertex. The point of the vertex is encoded into the equation: we know that the vertex is at the point $(2.4, 13)$. And since the value of $a$ in the quadratic is negative (-2.1), we know that the vertex is the maximum.

[zenith sedge]

starhands

[royal leaf]

is the height 0.904m

[jade creek]

u got it

@royal leaf did you need help with anything else? if not, please type ".close" to close this help thread

[serene gazelle]

I saw the exponent but didn't think about it being quadratic. That makes sense. Smart! 🙂

[serene gazelle]

That makes sense. Smart! 🙂