Math Problem Statement

(1 point) NASA launches a rocket at t=0 seconds. Its height, in meters above sea-level, as a function of time is given by h(t)=−4.9t2+277t+395 .

Assuming that the rocket will splash down into the ocean, after how many seconds does splashdown occur? Round your answer to the nearest hundredth. The rocket splashes down after 57.96 functionsequation editor seconds.

How high above sea-level does the rocket get at its peak? Round your answer to the nearest hundredth.

The rocket peaks at functionsequation editor meters above sea-level.

Solution

We are given the height function of the rocket as:

h(t)=4.9t2+277t+395h(t) = -4.9t^2 + 277t + 395

1. Time of Splashdown:

To find the time when the rocket splashes down, we set h(t)=0h(t) = 0 (since it will be at sea level when it splashes down).

4.9t2+277t+395=0-4.9t^2 + 277t + 395 = 0

We solve this quadratic equation using the quadratic formula:

t=b±b24ac2at = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

Where:

  • a=4.9a = -4.9
  • b=277b = 277
  • c=395c = 395

Substitute the values into the quadratic formula:

t=277±27724(4.9)(395)2(4.9)t = \frac{-277 \pm \sqrt{277^2 - 4(-4.9)(395)}}{2(-4.9)} t=277±76729(7746)9.8t = \frac{-277 \pm \sqrt{76729 - (-7746)}}{-9.8} t=277±844759.8t = \frac{-277 \pm \sqrt{84475}}{-9.8} t=277±290.669.8t = \frac{-277 \pm 290.66}{-9.8}

Now, solve for the two possible values of tt:

  1. t1=277+290.669.8=13.669.81.396t_1 = \frac{-277 + 290.66}{-9.8} = \frac{13.66}{-9.8} \approx -1.396 (not physically meaningful as time cannot be negative).
  2. t2=277290.669.8=567.669.857.96t_2 = \frac{-277 - 290.66}{-9.8} = \frac{-567.66}{-9.8} \approx 57.96

Thus, the rocket splashes down at 57.96 seconds.

2. Maximum Height (Peak):

The maximum height occurs at the vertex of the parabola, which is given by the formula for the time at the vertex of a parabola:

tvertex=b2at_{\text{vertex}} = \frac{-b}{2a}

Substitute the values of a=4.9a = -4.9 and b=277b = 277:

tvertex=2772(4.9)=2779.828.3 secondst_{\text{vertex}} = \frac{-277}{2(-4.9)} = \frac{-277}{-9.8} \approx 28.3 \text{ seconds}

Now, substitute t=28.3t = 28.3 into the height equation to find the maximum height:

h(28.3)=4.9(28.3)2+277(28.3)+395h(28.3) = -4.9(28.3)^2 + 277(28.3) + 395 h(28.3)=4.9(801.29)+277(28.3)+395h(28.3) = -4.9(801.29) + 277(28.3) + 395 h(28.3)=3936.34+7830.11+395h(28.3) = -3936.34 + 7830.11 + 395 h(28.3)4288.77 metersh(28.3) \approx 4288.77 \text{ meters}

Thus, the rocket reaches a maximum height of 4288.77 meters above sea level.


Final Answers:

  • The rocket splashes down after 57.96 seconds.
  • The rocket reaches a peak height of 4288.77 meters.

Would you like more details or have any questions on this?

Further Questions:

  1. How does the coefficient 4.9-4.9 affect the rocket's trajectory?
  2. How do you calculate the maximum height of a parabola?
  3. What is the significance of the negative time solution in the quadratic equation?
  4. How would you graph this quadratic function to visualize the rocket's path?
  5. What would happen if the value of bb were increased?

Tip: When solving quadratic equations, always check both possible solutions, but discard those that don't make sense in the context (e.g., negative time in this case).

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Math Problem Analysis

Mathematical Concepts

Quadratic Equations
Projectile Motion
Parabolas

Formulas

Quadratic formula: t = (-b ± √(b² - 4ac)) / 2a
Vertex formula for parabolas: t_vertex = -b / 2a

Theorems

Quadratic Formula
Properties of Parabolas

Suitable Grade Level

Grades 9-11