Math Problem Statement

A car with a 44-inch diameter wheel is traveling at 45 mph. (Notes: round the answer to three decimal places.) Find the angular speed of the wheels in rad/min

Solution

To find the angular speed of the wheels in radians per minute, we can follow these steps:

Step 1: Convert the diameter of the wheel to its radius

The diameter of the wheel is 44 inches, so the radius rr is: r=44 inches2=22 inchesr = \frac{44 \text{ inches}}{2} = 22 \text{ inches}

Step 2: Convert the car's speed from miles per hour to inches per minute

First, convert the speed from miles per hour to inches per hour: 45 miles/hour×5280 feet/mile×12 inches/foot=2,851,200 inches/hour45 \text{ miles/hour} \times 5280 \text{ feet/mile} \times 12 \text{ inches/foot} = 2,851,200 \text{ inches/hour} Next, convert the speed to inches per minute: 2,851,200 inches/hour÷60 minutes/hour=47,520 inches/minute2,851,200 \text{ inches/hour} \div 60 \text{ minutes/hour} = 47,520 \text{ inches/minute}

Step 3: Find the number of wheel rotations per minute

The circumference CC of the wheel is: C=2πr=2π×22=44π inchesC = 2\pi r = 2\pi \times 22 = 44\pi \text{ inches} The number of rotations per minute NN is: N=Linear speed in inches/minuteCircumference of the wheel=47,520 inches/minute44π inches=47,52044πN = \frac{\text{Linear speed in inches/minute}}{\text{Circumference of the wheel}} = \frac{47,520 \text{ inches/minute}}{44\pi \text{ inches}} = \frac{47,520}{44\pi}

Step 4: Calculate the angular speed in radians per minute

The angular speed ω\omega in radians per minute is given by: ω=N×2π=47,52044π×2π=47,520×244=95,04044\omega = N \times 2\pi = \frac{47,520}{44\pi} \times 2\pi = \frac{47,520 \times 2}{44} = \frac{95,040}{44} ω2,160 radians per minute\omega \approx 2,160 \text{ radians per minute}

Thus, the angular speed of the wheels is approximately 2,160 radians per minute.

Do you want more details or have any questions? Here are 5 related questions for further exploration:

  1. How would the angular speed change if the wheel diameter was different?
  2. What is the relationship between linear and angular speed?
  3. How does angular speed change if the car accelerates?
  4. What if the car was traveling at a different speed—how would the angular speed change?
  5. Can you convert angular speed from radians per minute to degrees per minute?

Tip: Remember, the circumference of a wheel directly affects the number of rotations it makes for a given linear distance.

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Math Problem Analysis

Mathematical Concepts

Geometry
Trigonometry
Physics

Formulas

Circumference of a circle: C = 2\pi r
Linear speed conversion

Theorems

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Suitable Grade Level

Grades 10-12