3. A large wooden turntable has the shape of a flat uniform disk of radius 1.8 m and a total mass of 150 kg. The turntable is initially rotating at 4.00 rad/s about a vertical axis through its center. Suddenly, a 60 kg parachutist makes a soft landing near the outer edge. (a) Find the angular speed of the turntable after the parachutist lands. (Assume you can treat the parachutist as a particle.) (b) Compute the kinetic energy before and after the parachutist lands.

College Physics
11th Edition
ISBN:9781305952300
Author:Raymond A. Serway, Chris Vuille
Publisher:Raymond A. Serway, Chris Vuille
Chapter1: Units, Trigonometry. And Vectors
Section: Chapter Questions
Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...
icon
Related questions
Question
---

### Physics Problem: Rotational Motion of a Turntable

**Problem Statement:**

3. A large wooden turntable has the shape of a flat uniform disk of radius 1.8 m and a total mass of 150 kg. The turntable is initially rotating at 4.00 rad/s about a vertical axis through its center. Suddenly, a 60 kg parachutist makes a soft landing near the outer edge.

1. **(a)** Find the angular speed of the turntable after the parachutist lands. (Assume you can treat the parachutist as a particle.)
2. **(b)** Compute the kinetic energy before and after the parachutist lands.

**Detailed Explanation:**

To solve this problem, we will use the principles of conservation of angular momentum and kinetic energy.

#### (a) Angular Speed After Landing

1. **Calculate Initial Angular Momentum (L_initial)**
   - For a disk, the moment of inertia (I) is \( I = \frac{1}{2} m r^2 \), where \( m \) is the mass and \( r \) is the radius.
   - For the turntable: \( I_{turntable} = \frac{1}{2} \times 150 \text{ kg} \times (1.8 \text{ m})^2 \)
   - Calculate \( I_{turntable} \):

     \[
     I_{turntable} = \frac{1}{2} \times 150 \times 3.24 = 243 \text{ kg} \cdot \text{m}^2
     \]

   - Initial angular momentum \( L_{initial} \) is given by \( L = I \omega \):

     \[
     L_{initial} = 243 \times 4.00 = 972 \text{ kg} \cdot \text{m}^2 \cdot \text{s}^{-1}
     \]

2. **Calculate Final Angular Momentum (L_final)**
   - After the parachutist lands, the system's moment of inertia changes. Treat the parachutist as a point mass at the edge of the disk. The moment of inertia of the parachutist is \( I_{parachutist} = m r^2 \):

     \[
     I_{parachutist} = 60 \text{ kg} \
Transcribed Image Text:--- ### Physics Problem: Rotational Motion of a Turntable **Problem Statement:** 3. A large wooden turntable has the shape of a flat uniform disk of radius 1.8 m and a total mass of 150 kg. The turntable is initially rotating at 4.00 rad/s about a vertical axis through its center. Suddenly, a 60 kg parachutist makes a soft landing near the outer edge. 1. **(a)** Find the angular speed of the turntable after the parachutist lands. (Assume you can treat the parachutist as a particle.) 2. **(b)** Compute the kinetic energy before and after the parachutist lands. **Detailed Explanation:** To solve this problem, we will use the principles of conservation of angular momentum and kinetic energy. #### (a) Angular Speed After Landing 1. **Calculate Initial Angular Momentum (L_initial)** - For a disk, the moment of inertia (I) is \( I = \frac{1}{2} m r^2 \), where \( m \) is the mass and \( r \) is the radius. - For the turntable: \( I_{turntable} = \frac{1}{2} \times 150 \text{ kg} \times (1.8 \text{ m})^2 \) - Calculate \( I_{turntable} \): \[ I_{turntable} = \frac{1}{2} \times 150 \times 3.24 = 243 \text{ kg} \cdot \text{m}^2 \] - Initial angular momentum \( L_{initial} \) is given by \( L = I \omega \): \[ L_{initial} = 243 \times 4.00 = 972 \text{ kg} \cdot \text{m}^2 \cdot \text{s}^{-1} \] 2. **Calculate Final Angular Momentum (L_final)** - After the parachutist lands, the system's moment of inertia changes. Treat the parachutist as a point mass at the edge of the disk. The moment of inertia of the parachutist is \( I_{parachutist} = m r^2 \): \[ I_{parachutist} = 60 \text{ kg} \
Expert Solution
steps

Step by step

Solved in 3 steps

Blurred answer
Knowledge Booster
Rotational Kinetic energy
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.
Similar questions
Recommended textbooks for you
College Physics
College Physics
Physics
ISBN:
9781305952300
Author:
Raymond A. Serway, Chris Vuille
Publisher:
Cengage Learning
University Physics (14th Edition)
University Physics (14th Edition)
Physics
ISBN:
9780133969290
Author:
Hugh D. Young, Roger A. Freedman
Publisher:
PEARSON
Introduction To Quantum Mechanics
Introduction To Quantum Mechanics
Physics
ISBN:
9781107189638
Author:
Griffiths, David J., Schroeter, Darrell F.
Publisher:
Cambridge University Press
Physics for Scientists and Engineers
Physics for Scientists and Engineers
Physics
ISBN:
9781337553278
Author:
Raymond A. Serway, John W. Jewett
Publisher:
Cengage Learning
Lecture- Tutorials for Introductory Astronomy
Lecture- Tutorials for Introductory Astronomy
Physics
ISBN:
9780321820464
Author:
Edward E. Prather, Tim P. Slater, Jeff P. Adams, Gina Brissenden
Publisher:
Addison-Wesley
College Physics: A Strategic Approach (4th Editio…
College Physics: A Strategic Approach (4th Editio…
Physics
ISBN:
9780134609034
Author:
Randall D. Knight (Professor Emeritus), Brian Jones, Stuart Field
Publisher:
PEARSON