Question

Some fireworks are fired vertically into the air from the ground at an initial velocity of 80 feet per second. This motion can be modeled by the quadratic equation s(t) = -16t^2 + 80t. If a problem asks you to find how high the firework can go (this is the point where it explodes), what are they asking you for? (a) x coordinate of the vertex (b) y coordinate of the vertex (C) x coordinate of the roots (d) y coordinate of the roots

Answer 1

We are to know the highest point of the fireworks.

If we graph the quadratic, we will have a parabola with a maximum.

We basically want the maximum point. This occurs at the vertex.

• The x-coordinate of the vertex is at what time the maximum point occurs.

,

• The y-coordinate of the vertex is the exact height (max).

Thus, when we are asked to find how high the firework can go, we will find the y-coordinate of the vertex.

Answer(b) y coordinate of the vertex