Math Problem Statement

A ferris wheel is 35 meters in diameter and boarded from a platform that is 2 meters above the ground. The six o'clock position on the ferris wheel is level with the loading platform. The wheel completes 1 full revolution in 8 minutes. The function h = f(t) gives your height in meters above the ground t minutes after the wheel begins to turn. Write an equation for h = f(t).

Solution

To create the function h=f(t)h = f(t) for the height of a rider above the ground, let us analyze the problem step by step:

Key Information:

  1. Diameter: 35 meters → Radius r=352=17.5r = \frac{35}{2} = 17.5 meters.
  2. Platform Height: The loading platform is 2 meters above the ground.
  3. Period: The wheel completes one full revolution in 8 minutes, so the angular velocity is ω=2π8=π4\omega = \frac{2\pi}{8} = \frac{\pi}{4} radians per minute.
  4. Position: At t=0t = 0, the rider is at the lowest point of the ferris wheel.

Function Setup:

The ferris wheel motion is sinusoidal. The rider's height h(t)h(t) as a function of time tt can be modeled as: h(t)=Asin(ωt+ϕ)+Dh(t) = A \sin(\omega t + \phi) + D where:

  • AA: Amplitude (equal to the radius of the ferris wheel, 17.517.5).
  • ω\omega: Angular velocity (π4\frac{\pi}{4}).
  • ϕ\phi: Phase shift (determined based on starting position).
  • DD: Vertical shift (platform height + radius, 2+17.5=19.52 + 17.5 = 19.5).

Finding Phase Shift ϕ\phi:

  • At t=0t = 0, the rider is at the lowest point (h(0)=2h(0) = 2).
  • Substituting t=0t = 0 into the equation: 2=17.5sin(ϕ)+19.52 = 17.5 \sin(\phi) + 19.5 Simplify: sin(ϕ)=219.517.5=1\sin(\phi) = \frac{2 - 19.5}{17.5} = -1 Hence, ϕ=π2\phi = -\frac{\pi}{2}.

Final Equation:

h(t)=17.5sin(π4tπ2)+19.5h(t) = 17.5 \sin\left(\frac{\pi}{4}t - \frac{\pi}{2}\right) + 19.5 Simplify: h(t)=17.5cos(π4t)+19.5h(t) = 17.5 \cos\left(\frac{\pi}{4}t\right) + 19.5

Summary:

The height h(t)h(t) in meters above the ground is given by: h(t)=17.5cos(π4t)+19.5h(t) = 17.5 \cos\left(\frac{\pi}{4}t\right) + 19.5

Would you like a breakdown of the steps or help with related questions?


Expansion Questions:

  1. What would the equation be if the period of the wheel changed to 6 minutes?
  2. How does the phase shift (ϕ\phi) affect the position of the rider at t=0t = 0?
  3. Can we rewrite the equation using sine instead of cosine? How?
  4. What is the maximum and minimum height a rider reaches during the motion?
  5. How would the equation change if the platform height were raised to 5 meters?

Tip:

When modeling sinusoidal motion, always identify amplitude, vertical shift, angular velocity, and initial conditions to construct the equation systematically!

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Sinusoidal Functions
Periodic Motion

Formulas

h(t) = A * sin(ωt + φ) + D
ω = 2π / T

Theorems

Properties of Sinusoidal Functions
Relationship Between Angular Velocity and Period

Suitable Grade Level

Grades 9-12