PART–4 (ix) : IIT / JEE Previous Year Questions – Extreme Thinking & Rank-Decider Set
This set focuses on extreme cases, conceptual depth, and logic-based reasoning. These questions are designed to test whether a student truly understands Laws of Motion.
PYQ–41 (IIT–JEE Advanced)
Question:
A block of mass m is placed on a smooth horizontal surface. A force F acts on the block for a very short time. What physical quantity decides the change in motion of the block?
Method Selection:
Short time force problems require impulse–momentum concept.
Solution:
Change in momentum depends on impulse.
Impulse = F × Δt
Hence, change in momentum decides the change in motion.
Examiner’s Intention:
To test transition from force-based to momentum-based thinking.
PYQ–42 (IIT–JEE Advanced)
Question:
A body moves in a straight line such that its acceleration is always opposite to its velocity. What can you say about the motion?
Method Selection:
Direction-based analysis of acceleration.
Solution:
Acceleration opposite to velocity means speed decreases.
The body undergoes retarded motion.
Examiner’s Intention:
To check understanding of vector direction.
PYQ–43 (IIT–JEE Advanced)
Question:
A block is pushed with a constant force on a rough surface. The speed increases initially and then becomes constant. Explain this behavior.
Method Selection:
Analyze changing net force.
Solution:
Initially, applied force > friction ⇒ acceleration exists.
Later, friction balances applied force ⇒ net force becomes zero.
Hence, speed becomes constant.
Examiner’s Intention:
To test understanding of force balance over time.
PYQ–44 (IIT–JEE Advanced)
Question:
A body is projected vertically upward. Compare the magnitudes of acceleration at different points of motion.
Method Selection:
Ignore velocity, focus on force.
Solution:
At all points, only gravitational force acts.
Hence, acceleration magnitude remains constant (= g).
Examiner’s Intention:
To break misconception that acceleration depends on velocity.
PYQ–45 (IIT–JEE Advanced)
Question:
A block rests on a rough surface. A force is applied but the block does not move. What happens to the applied force?
Method Selection:
Static friction adjustment concept.
Solution:
The applied force is balanced by static friction.
Net force is zero, so the block remains at rest.
Examiner’s Intention:
To test understanding that static friction is self-adjusting.
Elite Thinking Reminders
- Impulse controls sudden changes, not force alone.
- Acceleration direction decides motion nature.
- Forces can change balance during motion.
- Acceleration can remain constant even if velocity changes.
- Static friction exists even without motion.
PART–4 (ix) Completed
📚 Physics Thinking Library – How IIT Toppers Think
Welcome to the Physics Thinking Library by Mind Grow Magazine. This library is specially designed for IIT–JEE & Intermediate students to understand how toppers think, decide, and solve Physics problems.
🎯 What You Will Learn From This Library
- How IIT toppers approach Physics questions
- Decision-making during problem solving
- Common traps & how to avoid them
- Exam-hall mindset and logic flow
- Step-by-step thinking framework
📘 Complete Series: How IIT Toppers Think (Part 1–25)
Click on any part below to start learning. It is recommended to read in order.
- Part 1 – Introduction to Topper Thinking
- Part 2 – Understanding the Problem Statement
- Part 3 – Visualization & Physical Sense
- Part 4 – Role of Acceleration & Forces
- Part 5 – Free Body Diagram Thinking
- Part 6 – Method Selection Strategy
- Part 7 – Avoiding Formula Traps
- Part 8 – System Approach Mindset
- Part 9 – Friction & Constraint Thinking
- Part 10 – Time vs Accuracy Balance
- Part 11 – Common Thinking Mistakes
- Part 12 – Decision Flow in Tough Problems
- Part 13 – Eliminating Wrong Options
- Part 14 – Handling Multi-Concept Questions
- Part 15 – Pressure Handling in Exam Hall
- Part 16 – Speed Building Without Guessing
- Part 17 – Extreme Case Thinking
- Part 18 – Logical Shortcuts vs Blind Tricks
- Part 19 – Advanced Reasoning Techniques
- Part 20 – Rank-Deciding Thought Patterns
- Part 21 – Physics Intuition Development
- Part 22 – Eliminating Panic in Tough Questions
- Part 23 – Last-Minute Thinking Strategy
- Part 24 – Mistake-Proof Problem Solving
- Part 25 – Final Topper Framework
🧠 How to Use This Library Effectively
- Read 1–2 parts daily
- Apply thinking to real Physics problems
- Revisit library before exams
- Use as a mindset guide, not memorization
This library is a long-term asset for serious Physics learners.
© Mind Grow Magazine
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