MDCAT Physics Common Mistakes: How to Stop Losing Marks on Easy Questions

Why MDCAT Physics Loses Marks on Easy Questions

Physics in MDCAT is only 36 MCQs, but students lose more marks here to careless mistakes than to genuinely hard questions. The 36 questions that do appear are usually straightforward applications of a single formula. The trap is in the execution: wrong units, wrong formula, wrong sign, or wrong interpretation of what the question is asking. Fixing these errors is faster than learning more physics.

Mistake 1: Unit Conversion Errors

This is the single most common mistake in MDCAT physics. A question gives values in cm, g, and minutes, but the formula requires metres, kg, and seconds. Students plug the numbers in directly and get an answer that matches one of the options — but the answer is off by a factor of 100 or 1000. Fix: before writing any formula, convert every value to SI units: cm to m (divide by 100), g to kg (divide by 1000), minutes to seconds (multiply by 60). Do this in the first 5 seconds of every numerical question.

Mistake 2: Falling for Extraneous Information

MDCAT physics questions sometimes include extra numbers that are not needed to solve the problem. Students who try to use every given number pick the wrong formula. Example: a projectile motion question gives the mass of the object even though projectile equations do not use mass. Only the initial velocity and angle matter. Fix: identify the physical principle being tested first, then ignore information that does not fit that principle.

Mistake 3: Sign and Direction Errors

Electrostatics and electromagnetism questions require sign awareness. Common errors: forgetting that the force on a negative charge is opposite to the electric field direction. Using the right-hand rule incorrectly for magnetic force. Treating vector quantities as scalars. Fix: draw a quick diagram showing the direction of forces, fields, and motion before writing any equations. A 10-second sketch prevents 90% of sign errors.

Mistake 4: Not Reading Qualifiers

Questions that say 'which of the following is NOT true' or 'which quantity remains constant, assuming no air resistance' are routinely misread. Students see a familiar concept and pick the first correct-looking answer without checking the qualifier. Fix: underline the qualifier word (NOT, EXCEPT, UNLESS, ASSUMING, ALWAYS) before reading the options. Then for 'NOT' questions, mark every option that IS true and pick the remaining one.

A 5-Step Checklist for Every Physics MCQ

Step 1: Read the last line first — know what is being asked. Step 2: Identify the physical principle. Step 3: Convert all values to SI units. Step 4: Underline any qualifier words. Step 5: Check if the answer makes physical sense — a car cannot travel at 1,000 m/s, a human cannot exert 100,000 N of force. If your answer is physically absurd, recheck your formula and units.