Work Energy and Simple Machines — Class 9 Science NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 9 Science chapter "Work Energy and Simple Machines" — 8 important questions with detailed answers for CBSE board exam preparation.
TL;DR: Free step-by-step NCERT solutions for Class 9 Science chapter "Work Energy and Simple Machines" — 8 important questions with detailed answers for CBSE…
By Syllab.in · Updated
Key Questions Covered:
- Define work. When is work zero?
- Calculate work done by a 50 N force displacing an object 10 m in the directio…
- Define kinetic energy and potential energy.
- + 5 more questions in the full chapter
Solutions Summary:
| Question | Status |
|---|---|
| Define work. When is work zero? | ✓ Solved |
| Calculate work done by a 50 N force displacing an object … | ✓ Solved |
| Define kinetic energy and potential energy. | ✓ Solved |
Showing 3 of 8 questions
Q1: Define work. When is work zero?
Work is the product of force and displacement in the direction of force.
Formula: W = F × d × cos θ
Where F = force, d = displacement, θ = angle between them
Work is zero when force is perpendicular to displacement (θ = 90°) or displacement is zero.
Q2: Calculate work done by a 50 N force displacing an object 10 m in the direction of force.
Step 1: F = 50 N, d = 10 m, θ = 0°
Step 2: W = F × d × cos(0°) = 50 × 10 × 1 = 500 J
Q3: Define kinetic energy and potential energy.
Kinetic energy is energy possessed by an object due to its motion.
Formula: KE = ½mv²
Potential energy is energy stored due to position or configuration.
Formula: PE = mgh (gravitational PE)
Both measured in Joules (J).
Showing 3 of 8 questions. Visit the full page for complete solutions.