Physics
Physics in the Pak Army Soldier Test checks SI units, motion, force, work and energy, simple electricity, and basic measurement. Questions test definitions and one-step calculations rather than lengthy derivations.
Core rules
- SI units: metre for length, kilogram for mass, second for time, newton for force, joule for energy, watt for power.
- Speed = distance/time. Velocity includes direction; speed does not.
- Newton's second law: force = mass x acceleration.
- Work = force x distance in the direction of force; energy is the capacity to do work.
- In a parallel circuit, voltage across branches is the same; in a series circuit, current is the same through components.
Worked example
A vehicle covers 150 km in 3 hours. Find its average speed. Speed = distance/time = 150/3 = 50 km/h. Reason: divide the total distance by the total time; the answer is an average, not the speed at every instant.
Traps
Do not confuse mass with weight: mass is in kilograms, weight is a force in newtons. Do not add distances in metres to times in minutes without converting. For work, a force that does not move the object through a distance does no work. Check whether a circuit is series or parallel before comparing current and voltage.
Exam focus
Write the formula, substitute values with units, and label the result. Memorize common SI units and the difference between scalar quantities, such as speed, and vector quantities, such as velocity.