Math Problem Statement

Jason jumped off a cliff, and his height as a function of time is modeled by h(t) = -16t^2 + 16t + 480. Solve for (a) the time to reach maximum height, (b) the highest point, and (c) when Jason hits the water.

Solution

From the provided image, let’s analyze and solve the problem step by step for clarity:

Given:

The function for Jason's height is: h(t)=16t2+16t+480h(t) = -16t^2 + 16t + 480 where tt is in seconds, and h(t)h(t) is in feet.


(a) How long did it take for Jason to reach his maximum height?

The time to reach the maximum height is found by using the formula for the vertex of a parabola: t=b2at = \frac{-b}{2a} Here:

  • a=16a = -16
  • b=16b = 16

Substituting: t=162(16)=1632=0.5seconds.t = \frac{-16}{2(-16)} = \frac{-16}{-32} = 0.5 \, \text{seconds}.

Answer: 0.5seconds0.5 \, \text{seconds}


(b) What was the highest point that Jason reached?

To find the maximum height, substitute t=0.5t = 0.5 into h(t)h(t): h(0.5)=16(0.5)2+16(0.5)+480h(0.5) = -16(0.5)^2 + 16(0.5) + 480

Calculate each term:

  • (0.5)2=0.25(0.5)^2 = 0.25
  • 16(0.25)=4-16(0.25) = -4
  • 16(0.5)=816(0.5) = 8

Adding these terms: h(0.5)=4+8+480=484feet.h(0.5) = -4 + 8 + 480 = 484 \, \text{feet}.

Answer: 484feet484 \, \text{feet}


(c) Jason hit the water after how many seconds?

To find when Jason hits the water, solve for tt when h(t)=0h(t) = 0: 16t2+16t+480=0-16t^2 + 16t + 480 = 0

Simplify by dividing through by 16-16: t2t30=0t^2 - t - 30 = 0

Factorize: (t6)(t+5)=0(t - 6)(t + 5) = 0

Solutions: t=6ort=5t = 6 \quad \text{or} \quad t = -5

Since time cannot be negative: t=6seconds.t = 6 \, \text{seconds}.

Answer: 6seconds6 \, \text{seconds}


Summary of Answers:

(a) 0.5seconds0.5 \, \text{seconds}
(b) 484feet484 \, \text{feet}
(c) 6seconds6 \, \text{seconds}


Do you want more details about any part of the solution, or have questions? Here are 5 additional questions you could consider:

  1. How would the equation change if Jason jumped from a higher platform?
  2. How can you derive the quadratic formula for solving part (c)?
  3. What does the negative coefficient of t2t^2 tell you about the graph of h(t)h(t)?
  4. Can you compute the time at which Jason was halfway down to the water?
  5. How would air resistance affect the height function?

Tip: Always double-check your factorizations or vertex calculations for quadratic equations!

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Vertex of a Parabola
Factoring Quadratic Equations

Formulas

Vertex formula t = -b / 2a
Substituting t to find maximum height h(t)
Solving quadratic equations by factoring

Theorems

Vertex Theorem for Quadratic Functions

Suitable Grade Level

Grades 9-11