9514 1404 393
Answer:
A) down
B) 25 m; 200 m/s
C) (20.41, 2065.82)
Explanation:
When you are first introduced to equations for ballistic motion, you may be told that the formula is ...
h(t) = -4.9t² +v₀t +h₀ . . . . . height in meters at time t seconds
where v₀ is the initial upward velocity in meters per second, and h₀ is the initial height in meters.
When you are first introduced to quadratic equations, and the vertex form in particular, you may be told that the form is ...
f(x) = a(x -h)² +k . . . . . . . vertex (h, k) and vertical scale factor 'a'
When the scale factor (or leading coefficient) is negative the graph of the parabola opens downward. When it is positive, the graph opens upward.
Knowing these things, you are prepared to match the given equation to these patterns.
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Part A: We observe that the leading coefficient of the function (-4.9) is negative, so the parabola opens down.
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Part B: The constant in the first given equation is 25, so the initial height is 25 meters.
The coefficient of t in the first given equation is 200, so the initial velocity of the rocket is 200 m/s.
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Part C: The vertex can be read from the second equation as ...
(h, k) = (20.41, 2065.82)