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Class 9 Physics Chapter 5 Work, Energy and Power: 13 Solved Previous Year Questions (2020–2025)
Work, Energy and Power is one of the most important chapters in Class 9 Physics, forming the foundation for higher studies in mechanics. This chapter explains how force causes objects to move, how energy transforms between forms, and why power matters in real-world applications—from a child riding a bicycle to a power plant generating electricity. Our collection of 13 solved previous year questions (2020–2025) from CBSE board exams helps you master every concept, from calculating work done against friction to understanding kinetic and potential energy. These questions reflect the exact format and difficulty level you'll face in your CBSE exams, making them invaluable for last-minute revision and confidence building.
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Understanding Work, Energy and Power: NCERT Chapter Overview
Chapter 5 of NCERT Class 9 Physics introduces three interconnected concepts: work (force × displacement), energy (capacity to do work), and power (rate of doing work). The chapter covers scalar quantities like work and energy, mechanical energy (kinetic and potential), conservation of energy, and practical applications in everyday life. Understanding these fundamentals is essential because they bridge kinematics and dynamics, forming the backbone of Class 10 and Class 11 physics curricula.
13 Solved CBSE Previous Year Questions: What to Expect
Our curated collection spans CBSE board exams from 2020 to 2025, including 1-mark, 2-mark, 3-mark, and 5-mark questions. These questions test conceptual clarity, numerical problem-solving, and real-world application skills. Common themes include: calculating work done by various forces, finding kinetic and potential energy, identifying energy transformations, and determining power in different scenarios. Each solution includes step-by-step working, formulas used, and common mistakes to avoid.
Work Done: Solved Questions on Force and Displacement
Work is defined as W = F × s × cos(θ) in NCERT Chapter 5. Previous year questions frequently ask students to calculate work done by gravity, friction, or applied forces. For example, finding work done by friction as an object slides down an incline, or calculating net work using the work-energy theorem. These questions teach why work is a scalar quantity and how direction matters (cosine factor). Understanding these helps solve complex multi-step problems involving varying forces.
Kinetic Energy and Potential Energy: Key Problem Types
Kinetic energy (KE = ½mv²) and potential energy (PE = mgh) are central to CBSE exams. Previous year papers feature questions like: finding KE of a moving object, calculating PE at various heights, and comparing energies in different scenarios. Students often confuse when to use which formula or forget units (Joules). Our solutions highlight the derivation from work-energy theorem, show how velocity doubling quadruples KE, and explain why PE is relative to a chosen reference point.
Conservation of Energy: Solved Examples and Applications
The law of conservation of mechanical energy (E = KE + PE = constant) appears in nearly every CBSE exam. Typical questions involve: verifying energy conservation in free fall, analyzing motion on frictionless surfaces, or explaining energy loss due to friction. Students must understand that total energy is conserved, but mechanical energy decreases when non-conservative forces act. Our solutions show energy bar graphs, step-by-step verification, and how to identify when this law applies versus when it doesn't.
Power: Rate of Doing Work – Previous Year Question Analysis
Power (P = W/t = F·v) measures how quickly work is done. CBSE questions test understanding of instantaneous power, average power, and unit conversions (Watts, kilowatts, horsepower). Common problems: finding power output of a motor lifting a load, calculating average power in climbing stairs, or comparing power ratings of appliances. Our solutions explain why identical work done in less time requires more power, and how power relates to efficiency in real machines.
Why CBSETUTOR.ai is India's Most-Used AI Tutor for CBSE Physics
CBSETUTOR.ai is the preferred 24x7 AI tutor for CBSE Classes 6–12 across India, trusted by lakhs of students and parents. For Work, Energy and Power, our AI instantly generates personalized practice questions, provides step-by-step solutions in both English and Hindi-medium, and adapts to each student's learning pace. Unlike static textbooks, our platform learns from your mistakes, identifies weak areas, and delivers targeted revision. Available on mobile and desktop, CBSETUTOR.ai has helped countless families improve their Physics grades through AI-powered doubt resolution and exam-ready content.
Common Mistakes in Work, Energy and Power Problems
Students frequently make errors like: forgetting the cosine factor in W = Fs cosθ, confusing mass and weight in PE calculations, using wrong reference points for potential energy, and applying conservation of energy when friction is present. Another common mistake is mixing up power and energy, or forgetting unit conversions (kWh vs Joules). Previous year solutions highlight these pitfalls, show how examiners mark partial credit, and teach strategies to avoid losing marks on careless errors.
How to Use These Previous Year Questions for Exam Prep
Start by reviewing NCERT Chapter 5 summary to refresh formulas and concepts. Then, solve questions by difficulty: 1-mark questions first for quick recall, followed by 2-mark and 3-mark problems requiring deeper understanding. Finally, tackle 5-mark questions that combine multiple concepts. Time yourself to match exam conditions (3-4 minutes per mark). Use our solutions not just to check answers, but to understand the reasoning. Revisit questions you got wrong after 2–3 days to reinforce learning and build conceptual confidence before board exams.
Numerical Problems: Step-by-Step Solutions with Formula Sheets
Our solved previous year questions include complete formula sheets and step-by-step numerical solutions. Each problem shows: given data, formula selection, substitution, calculation, and final answer with units. For example, a question asking 'A 2 kg object rises 5 m in 10 seconds. Find the power.' solution walks through PE = mgh = 2 × 10 × 5 = 100 J, then P = W/t = 100/10 = 10 W. This approach trains you to present solutions like CBSE examiners expect, maximizing marks in board exams.
Frequently asked questions
What topics are covered in NCERT Class 9 Physics Chapter 5 Work, Energy and Power?+
Chapter 5 covers work (force × displacement), kinetic energy, potential energy, mechanical energy conservation, power (rate of work), and real-world applications of these concepts in machines, sports, and daily life.
How many marks does Work, Energy and Power carry in CBSE Class 9 Physics exam?+
While chapter-wise mark distribution varies yearly, this chapter typically contributes 8–12% of the total Physics marks, appearing in both short-answer and long-answer questions across CBSE board exams.
Is CBSETUTOR.ai's AI tutor service free, or is there a paid plan?+
CBSETUTOR.ai offers a free trial period allowing you to explore our full platform—AI doubt resolution, personalized practice questions, video explanations, and mock exams—before choosing a subscription plan that suits your needs.
Does CBSETUTOR.ai provide Hindi-medium support for Class 9 Physics?+
Yes. CBSETUTOR.ai supports both English and Hindi-medium students with content, solutions, and AI doubt resolution available in Hindi, making Physics concepts clearer for regional learners across India.
What is the formula for calculating work done by a force?+
Work (W) = F × s × cos(θ), where F is force, s is displacement, and θ is the angle between force and displacement. When force is parallel to displacement, W = Fs; when perpendicular, W = 0.
How do kinetic and potential energy differ, and when do I use each?+
Kinetic energy (½mv²) depends on motion and speed; potential energy (mgh) depends on position and height. Use KE for moving objects and PE for objects at height. Together, they form total mechanical energy.
Can I access these 13 solved previous year questions on my phone?+
Yes. CBSETUTOR.ai is fully mobile-responsive. Download our app or access via browser on smartphone, tablet, or desktop to solve previous year questions anytime, anywhere, with offline reading features available.
Do these previous year solutions match the CBSE marking scheme?+
Absolutely. Our 13 solved questions are aligned with official CBSE marking schemes, showing how examiners distribute marks, which answers earn full credit, and where students typically lose marks in board exams.
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