Work and Energy — Flashcards
Karnataka Board · Class 9 · Science
20 flashcards for Work and Energy (Karnataka Board Class 9 Science) to test yourself on key terms and facts. Covers Work, Energy and Kinetic Energy.
Interactive on Super Tutor
Studying Work and Energy? Get the full interactive chapter.
Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for flashcards and more.
Free trial, no card needed.
What is the scientific definition of work? When is work said to be done?
Answer
Work is done when: 1. A force acts on an object 2. The object moves/displaces in the direction of force Work = Force × Displacement (W = F × s) Both conditions must be satisfied. If either force is z…
A porter lifts a 20 kg luggage to a height of 2 m. Calculate the work done. (g = 10 m/s²)
Answer
Given: m = 20 kg, h = 2 m, g = 10 m/s² Force needed = Weight = mg = 20 × 10 = 200 N Displacement = 2 m (upward) Work done = F × s = 200 N × 2 m = 400 J The porter does 400 J of work against gravity…
Why does a person get tired while holding a heavy bag stationary, even though no work is done scientifically?
Answer
Scientifically, no work is done because displacement = 0. However, the person gets tired because: 1. Muscles continuously contract to balance the weight 2. Energy is spent in maintaining muscle tensio…
What is energy? Give the relationship between work and energy.
Answer
Energy is the capacity to do work. Key points: • Energy enables objects to do work • Same unit as work (Joule) • When work is done ON an object, it gains energy • When work is done BY an object, it l…
A 5 kg ball is moving at 6 m/s. Calculate its kinetic energy.
Answer
Given: m = 5 kg, v = 6 m/s Formula: KE = ½mv² KE = ½ × 5 × (6)² KE = ½ × 5 × 36 KE = ½ × 180 KE = 90 J The kinetic energy of the ball is 90 J.
What happens to the kinetic energy of an object when its velocity is doubled?
Answer
When velocity is doubled: Original KE = ½mv² New KE = ½m(2v)² = ½m(4v²) = 4(½mv²) Result: KE becomes 4 times the original Example: If initial KE = 50 J and velocity doubles, New KE = 4 × 50 = 200 J…
Define potential energy and give the formula for gravitational potential energy.
Answer
Potential Energy: Energy possessed by an object due to its position or configuration. Gravitational Potential Energy: PE = mgh Where: • m = mass (kg) • g = acceleration due to gravity (9.8 m/s²) • h…
A 2 kg book is placed on a shelf 3 m high. Find its potential energy. (g = 10 m/s²)
Answer
Given: m = 2 kg, h = 3 m, g = 10 m/s² Formula: PE = mgh PE = 2 × 10 × 3 PE = 60 J The potential energy of the book is 60 J. This energy can be converted to kinetic energy if the book falls.
+12 more flashcards
Practise AllFrequently Asked Questions
What are the important topics in Work and Energy for Karnataka Board Class 9 Science?
How many flashcards are available for Work and Energy?
How should I revise Work and Energy for Class 9 exams?
Sources & Official References
- Karnataka SSLC — kseeb.kar.nic.in
- Dept of Pre-University Education, Karnataka
- National Education Policy 2020 — education.gov.in
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
More resources for Work and Energy
For serious students
Get the full Work and Energy chapter — start free.
Quizzes, flashcards, an AI doubt solver and a study plan for Karnataka Board Class 9 Science. Free to start, no card needed.