IEMJEE Physics preparation: Conservation of momentum — practice worksheet with answers

How to use this worksheet

This independent worksheet checks conservation of momentum with a new problem, an explanation task and an interleaved related skill. It is not an official IEM question paper, a difficulty forecast or a prescribed timed examination.

Write an attempt first, then compare your method with the visible answers. Record whether a miss came from interpretation, a missing concept, execution or a condition you overlooked.

Question 1: apply the topic

Does kinetic energy necessarily remain constant in that sticking collision?

Answer and checking point

No. Momentum is conserved under the assumption, but the collision is inelastic.

Check dimensions, direction and limiting behaviour. Ask whether the answer should increase or decrease when an input changes. A dimensional check is necessary in many calculations but cannot certify an omitted dimensionless coefficient or an inappropriate physical model.

Question 2: diagnose an approach

Explain why the following warning matters and identify the correction it calls for: Conservation of momentum does not automatically imply conservation of kinetic energy.

Model checkpoint: Total momentum stays constant for a system with no net external impulse over the interaction. Governing rule: Σp_before=Σp_after under the stated system conditions.

Question 3: transfer to power and energy transfer rates

A 20 N force acts along velocity 5 m/s. Find instantaneous power.

Answer: Fv=20×5=100 W.

This is an interleaved related-skill task, not a claim that the two topics have identical methods. Explain which idea changes when switching from the main topic to this one.

Review the attempt

Separate correct answers reached with a justified method from lucky guesses. Rework missed steps without looking at the answer, then use a fresh problem from an appropriate primary textbook or official paper. Do not use a small worksheet result as an admission cutoff, rank or readiness guarantee.

Official sources and verification

Sources checked on 26 October 2026. A source’s date, programme and campus limit which claims it supports. Official pages may change after review.

1. UEM — IEMJEE examination information

   Historical examination pattern; verify the current cycle on the central portal.

2. NTA — explicitly labelled JEE Main 2026 syllabus

   Historical PCM syllabus reference. Lessons and exercises are independently authored, not official IEMJEE papers or verified 2027 paper predictions.

3. NCERT — official textbook catalogue

   Primary textbook reference for checking school-level concepts. This directory does not certify the independent lesson or establish IEM examination weightage.

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