Math Problem Statement

Find the domain of the function h(t) = -16t^2 + 80t.

Solution

Let's tackle these problems step by step! Here's the breakdown and solution for each question:


5. Domain of the function h(t)=16t2+80th(t) = -16t^2 + 80t:

  • The height function models the projectile's motion.
  • To find the domain, determine the time interval tt during which the object is in motion (when h(t)0h(t) \geq 0).
  1. Solve h(t)=16t2+80t=0h(t) = -16t^2 + 80t = 0: Factorize: t(16t+80)=0    t=0ort=5t(-16t + 80) = 0 \implies t = 0 \, \text{or} \, t = 5 The object is on the ground at t=0t = 0 and t=5t = 5.

  2. Since h(t)h(t) represents height, the domain is: [0,5]seconds.[0, 5] \, \text{seconds}.


6. Maximum height for h(t)=16t2+110t+10h(t) = -16t^2 + 110t + 10:

  • This quadratic equation is downward-opening (16t2-16t^2), so the maximum height occurs at the vertex.
  1. Find the time of the vertex: t=b2a=1102(16)=11032=3.4375seconds.t = -\frac{b}{2a} = -\frac{110}{2(-16)} = \frac{110}{32} = 3.4375 \, \text{seconds}.

  2. Substitute t=3.4375t = 3.4375 into h(t)h(t): h(3.4375)=16(3.4375)2+110(3.4375)+10=198.06feet.h(3.4375) = -16(3.4375)^2 + 110(3.4375) + 10 = 198.06 \, \text{feet}. The maximum height is approximately 198.06 feet.


7. Eva's trampoline jump h(t)=16t2+20t+6h(t) = -16t^2 + 20t + 6:

  • Determine if Eva reaches h(t)=14h(t) = 14 feet.
  1. Solve 16t2+20t+6=14-16t^2 + 20t + 6 = 14: Simplify: 16t2+20t8=0    8(2t22.5t+1)=0.-16t^2 + 20t - 8 = 0 \implies -8(2t^2 - 2.5t + 1) = 0. Divide through by 8-8: 2t22.5t+1=0.2t^2 - 2.5t + 1 = 0.

  2. Use the quadratic formula: t=b±b24ac2a,a=2,b=2.5,c=1.t = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}, \, a = 2, b = -2.5, c = 1. t=(2.5)±(2.5)24(2)(1)2(2)=2.5±6.2584.t = \frac{-(-2.5) \pm \sqrt{(-2.5)^2 - 4(2)(1)}}{2(2)} = \frac{2.5 \pm \sqrt{6.25 - 8}}{4}. t=2.5±1.754.t = \frac{2.5 \pm \sqrt{-1.75}}{4}. Since the discriminant (1.75-1.75) is negative, **Eva does not reach

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Projectile Motion
Domain of a Function

Formulas

h(t) = -16t^2 + 80t
Factoring
Quadratic Equation (h(t) = 0)

Theorems

Factoring Quadratic Equations
Domain of Functions

Suitable Grade Level

Grades 9-10