Model before calculating
Use motion, circuit and matter-wave relations.
The idea
Record assumptions such as negligible air resistance and non-relativistic speed. Pick the physical relation that matches those assumptions before inserting values.
A method to try
- Separate horizontal and vertical motion.
- Find parallel resistance or sum branch powers.
- Use proportional reasoning when only a ratio is asked.
Follow the reasoning.
A cart moves horizontally at 5 m/s for 4 seconds with no horizontal acceleration. How far does it travel?
- The constant horizontal velocity permits displacement = velocity × time, giving 20 m.
- If the cart simultaneously moved vertically, that vertical motion would not change this calculation under the stated zero-horizontal-acceleration assumption. Resolve components instead of mixing them.
- Always identify the interval and assumptions first. A velocity at one instant cannot be multiplied by time if the velocity changes over that interval without using an average or another motion relation.
Think it through first.
At a fixed voltage, what happens to a resistor’s power when its resistance doubles?
Show the explanation
The power halves.
P = V²/R at fixed V. Specify what remains fixed; at fixed current, P = I²R would give a different relationship.
Make it your own
After reading, explain the method in your own words and identify the condition that makes it valid. Then try the linked starter practice without referring back to the worked example. Review the reasoning behind an error before repeating the same item; remembering an answer is different from being able to solve a new problem.
This lesson is one part of a short starter pathway. It does not cover the full exam syllabus or establish a predicted score.
Official references
These provider and publisher links explain the exam or underlying concepts. Our lessons and questions are original, independent practice.
View 8 references and checked dates
- NTA: 2026 information bulletin (opens in a new tab)Checked 2026-09-20
Observed PDF linked as IB 2026 from the official bulletin page; format on printed pages 11–12.
- NTA: 2026 syllabus (opens in a new tab)Checked 2026-09-20
Observed PDF linked from the official JEE Main site.
- NTA: JEE Main portal (opens in a new tab)Checked 2026-09-20
- OpenStax Calculus Volume 1 — 5.5 Substitution (opens in a new tab)Checked 2026-09-20
Concept and scope reference. Our questions and explanations are original; no provider endorsement.
- OpenStax University Physics Volume 3 — 6.2 Photoelectric Effect (opens in a new tab)Checked 2026-09-20
Concept and scope reference. Our questions and explanations are original; no provider endorsement.
- OpenStax Chemistry 2e — 11.4 Colligative Properties (opens in a new tab)Checked 2026-09-20
Concept and scope reference. Our questions and explanations are original; no provider endorsement.
- OpenStax Chemistry 2e — 13.4 Equilibrium Calculations (opens in a new tab)Checked 2026-09-20
Concept and scope reference. Our questions and explanations are original; no provider endorsement.
- OpenStax Chemistry 2e — 7.6 Molecular Structure and Polarity (opens in a new tab)Checked 2026-09-20
Concept and scope reference. Our questions and explanations are original; no provider endorsement.