Previous IIT / JEE Objective Questions
Work, Energy & Power – PAGE 2
This page focuses on slightly tougher objective questions frequently asked in IIT-JEE Main & Advanced. Each question highlights a specific trap or concept.
Q16. (IIT-JEE)
A particle of mass m moves under a force F = kx. Starting from rest at x = 0, its kinetic energy at x = a is:
Answer: ½ka²
Solution Method:
Use work–energy theorem.
KE = ∫₀ᵃ kx dx = ½ka²
Trap: Acceleration is not constant → equations of motion fail.
Q17. (JEE Main)
A block slides on a smooth surface and compresses a spring. At maximum compression, which quantity is zero?
Answer: Velocity
Explanation:
- Velocity = 0
- Acceleration ≠ 0
- Force ≠ 0
Q18. (IIT-JEE)
A particle moves with constant speed in a vertical circle. Work done by gravity over one complete revolution is:
Answer: 0
Reason:
Initial and final heights are same → no net work.
Q19. (JEE Main)
If momentum of a particle is increased by 50%, kinetic energy increases by:
Answer: 125%
Logic:
KE ∝ p² → (1.5)² = 2.25 → Increase = 125%
Q20. (IIT-JEE)
A body is moving upward under gravity. At what point is kinetic energy minimum?
Answer: At the highest point
Explanation:
Velocity is minimum (zero) at the top.
Q21. (JEE Main)
Which of the following forces is conservative?
Answer: Gravitational force
Why:
Work done depends only on initial and final positions.
Q22. (IIT-JEE)
A particle moves on a rough surface with constant speed. Which statement is correct?
Answer: Net work done is zero
Explanation:
Constant speed → ΔKE = 0 → Net work = 0
Trap: Individual forces may still do work.
Q23. (JEE Main)
The dimensional formula of work is:
Answer: ML²T⁻²
Method:
Work = Force × distance
Q24. (IIT-JEE)
A block slides down a frictionless track of any shape. Speed at the bottom depends on:
Answer: Vertical height only
Key Insight:
Gravity is a conservative force.
Q25. (JEE Main)
At turning point of a particle in a potential field, which condition is satisfied?
Answer: Total energy = Potential energy
Reason:
KE = 0 at turning point.
End of PAGE 2
PAGE 2 emphasizes logic-based objective solving — not heavy calculation.
Work, Energy & Power – Complete Physics Library
This is the MASTER LIBRARY PAGE for the complete chapter Work, Energy and Power, prepared for Intermediate, IIT-JEE (Main & Advanced), NEET and competitive exams.
All concepts are explained from basic to IIT level, including theory, derivations, numerical problems, objective questions, previous year questions, tough IIT problems, tricks and cautions.
📚 Complete Lesson Index (Part 1 – Part 39)
- Part 1 – Introduction to Work
- Part 2 – Types of Work
- Part 3 – Variable Force & Graphs
- Part 4 – Kinetic Energy
- Part 5 – Work–Energy Theorem
- Part 6 – Potential Energy
- Part 7 – Conservative Forces
- Part 8 – Mechanical Energy
- Part 9 – Power
- Part 10 – Power Applications
- Part 11
- Part 12
- Part 13
- Part 14
- Part 15
- Part 16
- Part 17
- Part 18
- Part 19
- Part 20
- Part 21
- Part 22
- Part 23
- Part 24
- Part 25
- Part 26
- Part 27
- Part 28
- Part 29
- Part 30
- Part 31
- Part 32
- Part 33
- Part 34
- Part 35
- Part 36
- Part 37
- Part 38
- Part 39 – Final IIT Tough Problems & Solutions
Prepared by: Shaktimatha Learning 🌱
Strong Concepts • Smart Practice • Exam Success
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