Physics
Core ideas
Mechanics rests on kinematics, Newton’s three laws, and energy conservation. Draw a free-body diagram before writing equations; resolve forces along and perpendicular to motion. In fluids, distinguish gauge pressure from absolute pressure, apply continuity and Bernoulli’s equation to steady ideal flow, and use Archimedes’ principle for buoyancy. Thermodynamics questions test heat transfer, specific heat, latent heat, and the gas laws; keep temperatures in kelvin for gas calculations. Electricity and magnetism require Ohm’s law, series and parallel rules, power, and the direction of magnetic force on a current or moving charge. Aeronautical applications link these ideas to lift, drag, thrust, and weight: lift depends on airspeed, wing area, air density, and angle of attack.
Traps
Common traps are confusing mass with weight, using degrees Celsius in gas-law problems, treating gauge pressure as absolute, ignoring the direction of friction, and adding resistors in parallel as if they were in series. In lift questions, do not assume that a larger angle of attack always increases lift; beyond the critical angle the wing stalls.
Worked example
A 12 V battery drives a 4 Ω resistor. Current I = V/R = 12/4 = 3 A; power P = VI = 36 W. Rule of thumb: write units beside every number; if the units do not cancel to the expected unit, the equation is probably wrong.