By the Tadrees team
Numerical questions are where many students lose marks in physics, not because the physics is hard but because the method is rushed. A calm, repeatable routine removes most errors. Follow these steps for every numerical question and you will become both faster and more accurate.
List the known quantities with their symbols and units, then write the unknown. For example: mass m = 5.0 g, radius r = 6.0 cm, speed v = 1.2 m/s, find centripetal acceleration a. This takes ten seconds and prevents the most common error, which is using the wrong number in the wrong place.
Most formulas in your textbook assume SI units: metres, kilograms, seconds, newtons, joules. If a question gives centimetres, grams or kilometres per hour, convert first. In the example above, 6.0 cm becomes 0.060 m. Mixing units is the single biggest source of wrong answers, and exam setters know it, so wrong options are often the answers you get by forgetting to convert.
Look at the quantities you have and the one you want, and pick the formula that contains exactly those. If it contains an extra unknown, you may need a second formula first. Writing the formula in symbols before substituting numbers also helps you catch mistakes, and in many questions you can simplify the symbols before using the calculator.
Get a rough idea of the size of the answer. If a car of 1000 kg is pushed by a force of 500 N, you know the acceleration is going to be less than 1 m/s². A quick estimate lets you reject options that are off by a factor of ten or a hundred, which are common distractors, even before you compute exactly.
Use scientific notation for very large or very small numbers. Check that you squared or square-rooted the right quantity, because slips like using v instead of v² are easy to make. Keep a few extra digits during the calculation and round only at the end.
The final answer must have the right unit. If you were asked for acceleration and your unit works out as m/s, something went wrong. Also ask whether the size makes sense: a person's walking speed of 150 m/s or a mass of 0.0001 kg for a book are signs of an error.
After you learn a formula, work through the textbook's solved examples without looking at the solution, then compare. Then try similar questions with different numbers. Once the method is automatic, MCQ numericals take under a minute. Topic-wise practice with explanations, like the numerical questions on Tadrees, lets you repeat this cycle until each formula feels familiar.
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