A 28-kg girl is bouncing on a trampoline. During a certain interval after leaving the surface of the trampoline, her kinetic energy decreases to 220 J from 420 J. How high does she rise during this interval? Neglect air resistance.

Elements Of Electromagnetics
7th Edition
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Sadiku, Matthew N. O.
ChapterMA: Math Assessment
Section: Chapter Questions
Problem 1.1MA
icon
Related questions
Question
**Physics Problem Explanation: Trampoline Kinetic Energy**

**Problem Statement:**
A 28-kg girl is bouncing on a trampoline. During a certain interval after leaving the surface of the trampoline, her kinetic energy decreases to 220 J from 420 J. How high does she rise during this interval? Neglect air resistance.

**Solution:**

To solve this problem, we can use the principle of conservation of energy. The loss in kinetic energy will equal the gain in potential energy as she rises.

1. Initial kinetic energy (\(KE_i\)) = 420 J
2. Final kinetic energy (\(KE_f\)) = 220 J

**Step 1: Calculate the change in kinetic energy:**

\[
\Delta KE = KE_i - KE_f
\]

\[
\Delta KE = 420 \text{ J} - 220 \text{ J} = 200 \text{ J}
\]

**Step 2: Relate this change to potential energy:**

The change in kinetic energy will be equal to the change in potential energy since air resistance is neglected:

\[
\Delta KE = \Delta PE
\]

**Step 3: Use the potential energy formula:**

Potential energy (\(PE\)) gained by the girl as she rises:

\[
PE = mgh
\]

Where:
- \(m\) is the mass (28 kg)
- \(g\) is the acceleration due to gravity (9.8 m/s²)
- \(h\) is the height she rises

**Step 4: Solve for height (\(h\)):**

\[
200 \text{ J} = (28 \text{ kg})(9.8 \text{ m/s}^2)(h)
\]

\[
200 \text{ J} = 274.4 \text{ kg} \cdot \text{m/s}^2 \cdot h
\]

\[
h = \frac{200 \text{ J}}{274.4 \text{ kg} \cdot \text{m/s}^2}
\]

\[
h \approx 0.73 \text{ m}
\]

**Conclusion:**
The girl rises approximately 0.73 meters during this interval when her kinetic energy decreases from 420 J to 220 J.
Transcribed Image Text:**Physics Problem Explanation: Trampoline Kinetic Energy** **Problem Statement:** A 28-kg girl is bouncing on a trampoline. During a certain interval after leaving the surface of the trampoline, her kinetic energy decreases to 220 J from 420 J. How high does she rise during this interval? Neglect air resistance. **Solution:** To solve this problem, we can use the principle of conservation of energy. The loss in kinetic energy will equal the gain in potential energy as she rises. 1. Initial kinetic energy (\(KE_i\)) = 420 J 2. Final kinetic energy (\(KE_f\)) = 220 J **Step 1: Calculate the change in kinetic energy:** \[ \Delta KE = KE_i - KE_f \] \[ \Delta KE = 420 \text{ J} - 220 \text{ J} = 200 \text{ J} \] **Step 2: Relate this change to potential energy:** The change in kinetic energy will be equal to the change in potential energy since air resistance is neglected: \[ \Delta KE = \Delta PE \] **Step 3: Use the potential energy formula:** Potential energy (\(PE\)) gained by the girl as she rises: \[ PE = mgh \] Where: - \(m\) is the mass (28 kg) - \(g\) is the acceleration due to gravity (9.8 m/s²) - \(h\) is the height she rises **Step 4: Solve for height (\(h\)):** \[ 200 \text{ J} = (28 \text{ kg})(9.8 \text{ m/s}^2)(h) \] \[ 200 \text{ J} = 274.4 \text{ kg} \cdot \text{m/s}^2 \cdot h \] \[ h = \frac{200 \text{ J}}{274.4 \text{ kg} \cdot \text{m/s}^2} \] \[ h \approx 0.73 \text{ m} \] **Conclusion:** The girl rises approximately 0.73 meters during this interval when her kinetic energy decreases from 420 J to 220 J.
Expert Solution
steps

Step by step

Solved in 3 steps with 2 images

Blurred answer
Knowledge Booster
Forms of Energy
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
Elements Of Electromagnetics
Elements Of Electromagnetics
Mechanical Engineering
ISBN:
9780190698614
Author:
Sadiku, Matthew N. O.
Publisher:
Oxford University Press
Mechanics of Materials (10th Edition)
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:
9780134319650
Author:
Russell C. Hibbeler
Publisher:
PEARSON
Thermodynamics: An Engineering Approach
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:
9781259822674
Author:
Yunus A. Cengel Dr., Michael A. Boles
Publisher:
McGraw-Hill Education
Control Systems Engineering
Control Systems Engineering
Mechanical Engineering
ISBN:
9781118170519
Author:
Norman S. Nise
Publisher:
WILEY
Mechanics of Materials (MindTap Course List)
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:
9781337093347
Author:
Barry J. Goodno, James M. Gere
Publisher:
Cengage Learning
Engineering Mechanics: Statics
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:
9781118807330
Author:
James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:
WILEY