Math Problem Statement

A wheel rotating about a fixed axis with a constant angular acceleration of 3.0 rad/s2 starts from rest at t = 0. The wheel has a diameter of 40 cm. What is the magnitude of the total linear acceleration of a point on the outer edge of the wheel at t = 0.60 s?

Solution

To find the total linear acceleration of a point on the outer edge of the wheel at t=0.60st = 0.60 \, \text{s}, we need to calculate two components of acceleration:

  1. Tangential acceleration (ata_t): This is due to the angular acceleration of the wheel.
  2. Centripetal acceleration (aca_c): This arises because the point on the wheel is moving in a circular path.

The total linear acceleration is the vector sum of these two components:

atotal=at2+ac2a_{\text{total}} = \sqrt{a_t^2 + a_c^2}


Step 1: Calculate Tangential Acceleration (ata_t)

The tangential acceleration is given by:

at=αra_t = \alpha r

where:

  • α=3.0rad/s2\alpha = 3.0 \, \text{rad/s}^2 (angular acceleration),
  • r=diameter2=40cm2=0.20mr = \frac{\text{diameter}}{2} = \frac{40 \, \text{cm}}{2} = 0.20 \, \text{m} (radius).

at=3.0×0.20=0.60m/s2a_t = 3.0 \times 0.20 = 0.60 \, \text{m/s}^2


Step 2: Calculate Centripetal Acceleration (aca_c)

The centripetal acceleration is given by:

ac=ω2ra_c = \omega^2 r

where:

  • ω\omega (angular velocity) at t=0.60st = 0.60 \, \text{s} is found using:

ω=αt\omega = \alpha t

Substituting α=3.0rad/s2\alpha = 3.0 \, \text{rad/s}^2 and t=0.60st = 0.60 \, \text{s}:

ω=3.0×0.60=1.8rad/s\omega = 3.0 \times 0.60 = 1.8 \, \text{rad/s}

Now calculate aca_c:

ac=(1.8)2×0.20=3.24×0.20=0.648m/s2a_c = (1.8)^2 \times 0.20 = 3.24 \times 0.20 = 0.648 \, \text{m/s}^2


Step 3: Calculate Total Linear Acceleration (atotala_{\text{total}})

Combine the components ata_t and aca_c:

atotal=at2+ac2a_{\text{total}} = \sqrt{a_t^2 + a_c^2}

Substitute at=0.60m/s2a_t = 0.60 \, \text{m/s}^2 and ac=0.648m/s2a_c = 0.648 \, \text{m/s}^2:

atotal=(0.60)2+(0.648)2=0.36+0.419904=0.779904a_{\text{total}} = \sqrt{(0.60)^2 + (0.648)^2} = \sqrt{0.36 + 0.419904} = \sqrt{0.779904}

atotal0.884m/s2a_{\text{total}} \approx 0.884 \, \text{m/s}^2


Final Answer:

The magnitude of the total linear acceleration is approximately:

0.88m/s2\boxed{0.88 \, \text{m/s}^2}


Do you want further details or have any questions? Here are 5 related questions to consider:

  1. How does angular acceleration affect the tangential acceleration of a point on a rotating wheel?
  2. What role does the radius play in centripetal acceleration?
  3. How would the total acceleration change if the wheel’s angular acceleration doubled?
  4. Why is the centripetal acceleration zero at t=0t = 0?
  5. What is the relationship between linear acceleration and angular motion?

Tip: Always check the units of angular velocity and acceleration to ensure proper calculations!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Angular acceleration
Tangential acceleration
Centripetal acceleration
Vector addition
Circular motion dynamics

Formulas

Tangential acceleration: at = αr
Centripetal acceleration: ac = ω²r
Angular velocity: ω = αt
Total linear acceleration: a_total = √(at² + ac²)

Theorems

Pythagorean theorem (used to combine acceleration components)

Suitable Grade Level

Grades 10-12