Math Problem Statement

Starting from rest, a person pedals a bicycle such that the angular acceleration of the wheels is a constant 1.10 rad/s2. The bicycle wheels are 33.0 cm in radius. (a) What is the magnitude of the bicycle's linear acceleration (in m/s2)?

Correct: Your answer is correct. m/s2 (b) What is the angular speed of the wheels (in rad/s) when the linear speed of the bicyclist reaches 11.2 m/s? rad/s (c) How many radians have the wheels turned through in that time? rad (d) How far (in m) has the bicycle traveled in that time?

Solution

Let's solve each part step by step.

Given Data:

  • Angular acceleration of the wheels, α=1.10rad/s2\alpha = 1.10 \, \text{rad/s}^2
  • Radius of the wheels, r=33.0cm=0.33mr = 33.0 \, \text{cm} = 0.33 \, \text{m}

(a) Find the magnitude of the bicycle's linear acceleration.

The linear acceleration aa is related to the angular acceleration α\alpha by the formula: a=αra = \alpha \cdot r Substitute the values: a=1.10rad/s2×0.33m=0.363m/s2a = 1.10 \, \text{rad/s}^2 \times 0.33 \, \text{m} = 0.363 \, \text{m/s}^2

Answer: The linear acceleration is 0.363m/s20.363 \, \text{m/s}^2.


(b) Find the angular speed of the wheels when the linear speed of the bicyclist reaches 11.2m/s11.2 \, \text{m/s}.

The relationship between linear speed vv and angular speed ω\omega is: v=ωrv = \omega \cdot r Solving for ω\omega: ω=vr\omega = \frac{v}{r} Substitute the values: ω=11.2m/s0.33m=33.94rad/s\omega = \frac{11.2 \, \text{m/s}}{0.33 \, \text{m}} = 33.94 \, \text{rad/s}

Answer: The angular speed of the wheels is 33.94rad/s33.94 \, \text{rad/s}.


(c) Find how many radians the wheels have turned through in that time.

First, find the time tt it took for the bicycle to reach a linear speed of 11.2m/s11.2 \, \text{m/s}.

Using the linear acceleration a=0.363m/s2a = 0.363 \, \text{m/s}^2: v=att=va=11.2m/s0.363m/s2=30.86sv = a \cdot t \Rightarrow t = \frac{v}{a} = \frac{11.2 \, \text{m/s}}{0.363 \, \text{m/s}^2} = 30.86 \, \text{s}

Now, we use the angular displacement formula for constant angular acceleration: θ=ω0t+12αt2\theta = \omega_0 \cdot t + \frac{1}{2} \alpha t^2 Since the bicycle starts from rest, ω0=0\omega_0 = 0: θ=12αt2\theta = \frac{1}{2} \cdot \alpha \cdot t^2 Substitute the values: θ=12×1.10rad/s2×(30.86s)2\theta = \frac{1}{2} \times 1.10 \, \text{rad/s}^2 \times (30.86 \, \text{s})^2 θ=524.04rad\theta = 524.04 \, \text{rad}

Answer: The wheels have turned through 524.04radians524.04 \, \text{radians}.


(d) Find how far the bicycle has traveled in that time.

The linear distance ss traveled is related to the angular displacement θ\theta by: s=θrs = \theta \cdot r Substitute the values: s=524.04rad×0.33m=172.93ms = 524.04 \, \text{rad} \times 0.33 \, \text{m} = 172.93 \, \text{m}

Answer: The bicycle has traveled 172.93m172.93 \, \text{m}.


Summary of Answers:

  • (a) Linear acceleration: 0.363m/s20.363 \, \text{m/s}^2
  • (b) Angular speed: 33.94rad/s33.94 \, \text{rad/s}
  • (c) Angular displacement: 524.04rad524.04 \, \text{rad}
  • (d) Distance traveled: 172.93m172.93 \, \text{m}

Do you have any questions on these calculations or need further details?


Related Questions:

  1. How would the answers change if the wheel radius were different?
  2. What if the angular acceleration varied over time instead of being constant?
  3. How would the total time change if the linear speed was halved?
  4. What is the relationship between the linear and angular quantities in rotational motion?
  5. How do centripetal forces relate to the motion of a bicycle wheel?

Tip:

Always double-check units when converting between linear and angular motion to ensure consistent results.

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Math Problem Analysis

Mathematical Concepts

Rotational Kinematics
Linear and Angular Motion
Constant Angular Acceleration

Formulas

Linear acceleration a = α * r
Angular speed ω = v / r
Time t = v / a
Angular displacement θ = (1/2) * α * t²
Linear distance s = θ * r

Theorems

Relationships between linear and angular quantities in rotational motion

Suitable Grade Level

Grades 10-12