Math Problem Statement

A ball dropped from a height of 13 ft begins to bounce vertically. Each time it strikes the ground, it returns to two-thirds of its previous height. What is the total vertical distance traveled by the ball if it bounces infinitely many times? (Give your answer as a whole number.)

Solution

This problem involves summing up the total vertical distance traveled by the ball, which bounces infinitely, diminishing by a factor of 23\frac{2}{3} after each bounce.

Step 1: Breaking the problem into parts

  1. Initial drop: The ball falls from 13 ft.

    • Distance = 1313 ft.
  2. First bounce up: It rebounds 23\frac{2}{3} of the height.

    • Distance = 13×2313 \times \frac{2}{3}.
  3. First bounce down: The ball falls back down the same distance.

    • Distance = 13×2313 \times \frac{2}{3}.

    This pattern continues, forming an infinite geometric series for the bounces.

Step 2: Total distance formula

The total distance can be computed as: Total Distance=Initial Drop+2×Sum of all bounces up/down.\text{Total Distance} = \text{Initial Drop} + 2 \times \text{Sum of all bounces up/down}.

The series for bounces up/down is geometric: Sum of bounces=13×23+13×(23)2+13×(23)3+\text{Sum of bounces} = 13 \times \frac{2}{3} + 13 \times \left(\frac{2}{3}\right)^2 + 13 \times \left(\frac{2}{3}\right)^3 + \dots

This is an infinite geometric series with:

  • First term a=13×23a = 13 \times \frac{2}{3},
  • Common ratio r=23r = \frac{2}{3}.

The sum of an infinite geometric series is: Sum=a1r.\text{Sum} = \frac{a}{1 - r}.

Step 3: Calculating the total distance

  1. Compute the sum of bounces:
\quad r = \frac{2}{3}.$$ $$\text{Sum of bounces} = \frac{\frac{26}{3}}{1 - \frac{2}{3}} = \frac{\frac{26}{3}}{\frac{1}{3}} = 26.$$ 2. Total distance: $$\text{Total Distance} = 13 + 2 \times 26 = 13 + 52 = 65.$$ ### Final Answer: The total vertical distance traveled by the ball is: $$\boxed{65 \, \text{ft}}$$ Would you like a breakdown of a specific step or related examples? --- **Five related questions:** 1. What if the rebound height were $$\frac{1}{2}$$ instead of $$\frac{2}{3}$$? 2. How does the total distance change if the initial drop height is doubled? 3. How would you calculate the distance if the ball stops after a finite number of bounces? 4. Can the formula for geometric series be used for other physics problems? 5. What would happen to the total distance if the rebound factor were greater than 1? **Tip:** Always identify whether a problem involves infinite sequences or geometric series to simplify calculations.

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Math Problem Analysis

Mathematical Concepts

Infinite Series
Geometric Progression
Physics of Motion

Formulas

Sum of an infinite geometric series: S = a / (1 - r)
Total distance traveled by a bouncing ball: Initial height + 2 * Sum of bounces

Theorems

Geometric Series Sum Formula

Suitable Grade Level

Grades 9-11