CBSE Class 9 Physics Chapter 8 Force and Laws of Motion Worksheet with Answers
Force and Laws of Motion is a core chapter in CBSE Class 9 Physics, forming the foundation for mechanics in higher classes. This printable worksheet tests your understanding of balanced and unbalanced forces, Newton's three laws of motion, inertia, momentum and conservation principles. The worksheet is structured in six sections ranging from objective MCQs to case-study analysis, mirroring the actual CBSE exam pattern. Download, print and attempt this under timed conditions to assess your preparation.
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Key takeaways
- ✓Force is a push or pull; balanced forces cause no change in motion, unbalanced forces cause acceleration.
- ✓Newton's First Law defines inertia — objects resist change in their state of motion unless acted upon by unbalanced force.
- ✓Newton's Second Law quantifies force: F = m × a, connecting net force, mass and acceleration mathematically.
- ✓Newton's Third Law states every action has an equal and opposite reaction acting on different objects.
- ✓Momentum (p = m × v) is conserved in isolated systems — total momentum before collision equals total after collision.
- ✓This worksheet contains 40+ questions with full answer key, ideal for self-practice and pre-exam revision.
- ✓Suggested time: 60-75 minutes; difficulty: moderate to challenging, aligned with CBSE board pattern.
Quick Chapter Recap: Force and Laws of Motion
Before attempting the worksheet, refresh these fundamentals. A force is a push or pull that can change the state of motion or shape of an object, measured in Newtons (N). When multiple forces act on an object, their combined effect is the resultant or net force. Balanced forces have zero resultant and produce no change in motion. Unbalanced forces have non-zero resultant and cause acceleration. Newton's First Law (Law of Inertia) states that an object remains at rest or in uniform motion unless acted upon by an unbalanced force. Inertia is the resistance to change in motion; mass measures inertia quantitatively. Newton's Second Law is the equation F = m × a, showing that net force equals mass times acceleration. Newton's Third Law declares that every action force has an equal and opposite reaction force acting on a different object. Momentum is the product of mass and velocity (p = m × v), and the Law of Conservation of Momentum asserts that total momentum in an isolated system remains constant during interactions like collisions.
- Force: push or pull measured in Newtons (N)
- Balanced forces: resultant = 0, no change in motion
- Unbalanced forces: resultant ≠ 0, causes acceleration
- First Law: objects resist change in motion (inertia)
- Second Law: F = m × a (quantifies force-acceleration relationship)
- Third Law: action and reaction are equal, opposite, on different objects
- Momentum p = m × v, conserved in isolated systems
Section A: Multiple Choice Questions (MCQs)
This section contains six multiple-choice questions testing conceptual clarity and application skills. Each question has four options with only one correct answer. Marks: 1 mark per question. These MCQs cover Newton's laws, inertia, momentum and real-world scenarios like vehicle collisions and rocket propulsion. Read each question carefully, eliminate obviously wrong options and choose the best answer. In the CBSE board exam, MCQs carry significant weight, so practice them thoroughly. Attempting these MCQs will help you identify gaps in your understanding before moving to descriptive questions.
- Total questions: 6
- Marks per question: 1
- Total marks for Section A: 6
- Time suggested: 8–10 minutes
- Focus: conceptual clarity and quick decision-making
Section B: Fill in the Blanks
This section has five fill-in-the-blank statements designed to test recall of key definitions, formulae and conceptual terms from Chapter 8. Write the correct word or phrase in each blank. Marks: 1 mark per blank. These questions assess your memory of NCERT terminology and the precise language used to describe forces and motion. Pay attention to units, symbols and exact phrasing. CBSE examiners often award marks only when the exact term is used, so review your NCERT textbook definitions before attempting this section.
- Total blanks: 5
- Marks per blank: 1
- Total marks for Section B: 5
- Time suggested: 5 minutes
- Focus: accurate recall of definitions and terms
Section C: True or False Statements
This section presents six statements about Force and Laws of Motion. Write 'True' if the statement is correct or 'False' if it is incorrect. If false, write the correct statement in one line. Marks: 1 mark per statement. True/False questions test your ability to critically evaluate statements and identify misconceptions. Many students lose marks by not reading carefully—terms like 'always', 'never', 'only' often signal a false statement. This section trains you to think precisely about Newton's laws and their applications.
- Total statements: 6
- Marks per statement: 1 (1/2 for T/F, 1/2 for correction if false)
- Total marks for Section C: 6
- Time suggested: 8 minutes
- Focus: critical evaluation and precision
Section D: Short Answer Questions (2-3 marks each)
Section D contains five short-answer questions, each carrying 2 to 3 marks. Your answers should be concise—typically 30 to 50 words—and must include key terms, definitions or a brief worked example where asked. CBSE marking schemes reward answers that mention specific keywords and logical flow. Write in points wherever possible to make your answer clear and easy for the examiner to evaluate. These questions cover everyday applications, numerical problems and explanations of Newton's laws. Practising short-answer questions builds the skill of writing precise, exam-ready responses under time pressure.
- Total questions: 5
- Marks per question: 2–3
- Total marks for Section D: 12
- Time suggested: 20 minutes
- Focus: clarity, use of keywords, worked examples
Section E: Long Answer and HOTS Questions (5 marks each)
Section E has three long-answer or higher-order thinking (HOTS) questions, each worth 5 marks. These require detailed explanations, derivations or multi-step numerical problems. Your answer should be structured in clear paragraphs or numbered steps, include diagrams where helpful and show all working in calculations. CBSE awards step-wise marks, so even if your final answer is wrong, you can earn partial credit by showing correct method. Long-answer questions test deep understanding and the ability to connect concepts—vital for scoring well in board exams. Allocate sufficient time and write neatly.
- Total questions: 3
- Marks per question: 5
- Total marks for Section E: 15
- Time suggested: 25 minutes
- Focus: detailed explanations, derivations, complete working
Section F: Case Study Question
Case-study questions are now a standard part of CBSE exams, testing your ability to apply concepts to real-world scenarios. Read the passage carefully, extract relevant data and answer the sub-questions that follow. Marks: 4 (usually four sub-questions of 1 mark each). This section rewards analytical thinking and the ability to connect classroom physics to everyday phenomena. Many students find case studies challenging because they require interpretation, not just recall. Practice such questions to build confidence and exam readiness. The case study below involves a collision scenario, combining momentum conservation and Newton's laws.
- Total case studies: 1
- Sub-questions: 4
- Marks per sub-question: 1
- Total marks for Section F: 4
- Time suggested: 8–10 minutes
- Focus: interpretation, application of concepts
Answer Key with Explanations
Below is the complete answer key for all sections. Each answer includes a brief explanation or working to help you understand the concept and learn from mistakes. Cross-check your responses, award marks honestly and identify weak areas for revision. For numerical problems, ensure your units and steps match the solutions. If you scored below seventy per cent, revisit the NCERT chapter and solve additional problems. Consistent practice with worksheets like this one builds speed and accuracy—essential for CBSE board exams. Parents and students can also explore CBSETUTOR.ai for personalised doubt-clearing: upload a photo of any question and get instant step-by-step solutions, available 24×7 at a flat ₹999/month for all classes 6 to 12, with a three-day free trial.
How to Use This Worksheet Effectively
Print this worksheet and attempt it under exam-like conditions—set a timer for sixty to seventy-five minutes, avoid looking at notes and write answers on a separate sheet. After completion, check your answers against the answer key and award marks honestly. Identify topics where you made errors and revisit those sections in your NCERT textbook. Solve similar problems from the NCERT exercise and previous years' question papers. Repeat this process with different worksheets to build speed, accuracy and confidence. Regular practice transforms conceptual understanding into exam performance. If you struggle with any question, do not hesitate to ask your teacher or use digital tools. CBSETUTOR.ai offers round-the-clock doubt resolution: simply upload a photo of the problem and receive a detailed solution instantly, perfect for last-minute revision or when a teacher is unavailable. The platform covers all CBSE subjects for classes 6 to 12 at a single affordable price of ₹999 per month, with a three-day free trial to experience the service risk-free.
- Attempt the worksheet in one sitting under timed conditions
- Use a separate answer sheet, do not write on the question paper
- Self-assess using the answer key and mark honestly
- Identify weak areas and revise NCERT content
- Solve additional problems from textbook and sample papers
- Repeat with new worksheets to build consistency
Preparation Tips for Force and Laws of Motion
Chapter 8 is numerical-heavy and conceptually rich, so balance theory with problem-solving. First, read the NCERT chapter thoroughly, underlining definitions and laws. Make short notes summarising Newton's three laws, inertia, momentum and conservation principles. Practise derivations like F = ma and solve all NCERT in-text and end-of-chapter questions. Focus on units—force in Newtons, momentum in kg⋅m/s, acceleration in m/s²—and always write them in your answers. Draw free-body diagrams for force problems; visual representation clarifies which forces act on which object. Revise common misconceptions: action-reaction pairs act on different objects, not the same; mass and weight are different; inertia is not a force. Solve at least ten numerical problems daily in the week before your exam. Attempt previous years' CBSE question papers to understand the exam pattern and marking scheme. Group study helps—explain concepts to friends to deepen your own understanding. Finally, stay calm during the exam: read questions twice, underline keywords and manage time wisely across sections.
- Read NCERT chapter completely, underline key definitions
- Memorise Newton's three laws verbatim with examples
- Solve all NCERT in-text and exercise questions
- Practise numerical problems daily, focus on units and steps
- Draw free-body diagrams to visualise forces clearly
- Revise common misconceptions and clarify doubts immediately
- Attempt previous years' papers and sample papers under time limits
Frequently asked questions
What is the difference between mass and weight?+
Mass is the amount of matter in an object, measured in kilograms, and remains constant everywhere. Weight is the gravitational force on that mass (Weight = mass × g), measured in Newtons, and varies with location (less on Moon, more on Earth).
Why do we jerk forward when a bus stops suddenly?+
Our body is in motion along with the bus. When the bus stops, our lower body (in contact with the seat) stops, but our upper body continues moving forward due to inertia, causing the jerk. This is explained by Newton's First Law.
What is the SI unit of momentum and how is it derived?+
Momentum is p = m × v. SI unit of mass is kg and velocity is m/s, so momentum is measured in kg⋅m/s. Some books also write it as N⋅s (Newton-second), which is equivalent.
Can action and reaction forces cancel each other?+
No, they cannot cancel because they act on different objects. For forces to cancel (balance), they must act on the same object. Action-reaction pairs are equal and opposite but act on different bodies, so they do not affect each other's motion.
Is momentum conserved in all collisions?+
Momentum is conserved in all collisions (elastic and inelastic) provided the system is isolated—that is, no external forces like friction act on it. Kinetic energy may or may not be conserved, but total momentum always is in an isolated system.
How much time should I spend on this worksheet?+
Attempt this worksheet in sixty to seventy-five minutes to simulate exam conditions. Section A and B should take 15 minutes combined, Section C around 8 minutes, Section D 20 minutes, Section E 25 minutes and Section F 10 minutes. Adjust based on your speed.
What is the marking scheme for CBSE Physics numerical questions?+
CBSE awards step-wise marks: typically 1 mark for writing the correct formula, 1 mark for substituting given values, 1 mark for calculation and final answer with correct unit. Even if the final answer is wrong, you earn partial credit for correct method.
How can CBSETUTOR.ai help with Force and Laws of Motion?+
CBSETUTOR.ai offers 24×7 AI-powered doubt-solving. Upload a photo of any numerical or theory question from this chapter and receive instant step-by-step solutions with explanations. It covers all CBSE classes (6–12) at ₹999/month with a three-day free trial, perfect for quick revision and personalised learning.
What are common mistakes students make in this chapter?+
Common errors include confusing mass with weight, thinking action-reaction forces cancel, forgetting to write units, sign errors in momentum problems (direction matters), and not drawing free-body diagrams. Always read questions carefully and show all working in numerical problems.
Should I memorise all three laws word-by-word?+
Yes, CBSE expects you to state Newton's laws accurately in exams. Memorise the exact NCERT phrasing for definitions of each law and be ready to explain them with everyday examples. Marks are often awarded for precise language and correct terminology.
Related resources
Important Questions: CBSE Class 9 Physics Chapter 8 Force and Laws of MotionClass 9 Physics Chapter 8 Force and Laws of Motion — Formulas & Key PointsCBSE Class 9 Physics Chapter 8 Force and Laws of Motion — Complete NotesCBSE Class 9 Physics — Force and Laws of Motion: complete chapter guideCBSE Class 9 Mathematics Chapter 1 Number Systems — NotesCBSE Class 9 Mathematics — Number Systems: complete chapter guideClass 9 Physics Chapter 7: Motion – Complete Notes, Definitions & ExamplesCBSE Class 9 Mathematics Chapter 1 Number Systems Worksheet with Answers
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