Math Problem Statement

A rocket is launched from a tower. The height of the rocket, y in feet, is related to the time after launch, x in seconds, by the given equation. Using this equation, find the maximum height reached by the rocket, to the nearest tenth of a foot. y, equals, minus, 16, x, squared, plus, 170, x, plus, 85 y=−16x 2 +170x+85

Solution

The given equation for the height of the rocket is:

y=16x2+170x+85y = -16x^2 + 170x + 85

This is a quadratic equation in the standard form y=ax2+bx+cy = ax^2 + bx + c, where:

  • a=16a = -16
  • b=170b = 170
  • c=85c = 85

Step 1: Find the Time at Maximum Height

The maximum height of a quadratic function y=ax2+bx+cy = ax^2 + bx + c occurs at the vertex, given by:

x=b2ax = \frac{-b}{2a}

Substituting the values:

x=1702(16)x = \frac{-170}{2(-16)}

x=17032=5.3125 secondsx = \frac{170}{32} = 5.3125 \text{ seconds}

Step 2: Calculate the Maximum Height

Now, substitute x=5.3125x = 5.3125 into the height equation:

y=16(5.3125)2+170(5.3125)+85y = -16(5.3125)^2 + 170(5.3125) + 85

y=16(28.2344)+170(5.3125)+85y = -16(28.2344) + 170(5.3125) + 85

y=451.75+902.125+85y = -451.75 + 902.125 + 85

y=535.375y = 535.375

Final Answer:

The maximum height reached by the rocket is 535.4 feet (rounded to the nearest tenth).

Would you like a step-by-step breakdown of any part?

Here are some related questions to explore:

  1. How long does the rocket take to reach the ground?
  2. What is the initial height of the rocket?
  3. What is the total flight time of the rocket?
  4. At what time does the rocket reach a height of 400 feet?
  5. How does air resistance affect the rocket's motion?

Tip: The vertex formula is useful for finding maximum or minimum values in quadratic functions! 🚀

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Vertex of a Quadratic Function

Formulas

y = ax^2 + bx + c
x = -b / (2a)

Theorems

Vertex formula for quadratic functions

Suitable Grade Level

Grades 8-10