Physics: Mechanics, Heat, Waves and Electricity
What the paper tests
Core areas are measurement and units, kinematics and Newton's laws, work-energy-power, simple machines, heat and temperature, waves and sound, light, and basic electricity and magnetism. Most questions are conceptual with a few simple numericals.
Concepts to master
Distinguish scalar from vector quantities: speed and distance are scalars, velocity and displacement are vectors. Acceleration is change in velocity per unit time; a body moving in a circle at constant speed still accelerates because direction changes. Newton's second law gives F = ma; weight is mg, not mass. Work is force times displacement along the force; power is work per time. Know that heat and temperature differ, that specific heat capacity governs temperature change, and that latent heat applies during a change of state at constant temperature. For waves, v = f x wavelength; sound needs a medium. In electricity, Ohm's law V = IR, and power P = VI = I squared R.
Traps
Confusing mass with weight; assuming zero acceleration whenever speed is constant; forgetting that heat flows from hotter to colder bodies; mixing reflection and refraction; and using the wrong unit prefix (milli, kilo, micro).
Rule of thumb
Before computing, list the known quantities with SI units, then choose the equation containing exactly those quantities and one unknown. If two quantities are unknown, a second relation is needed.
Worked example
A 2 kg body accelerates at 3 m/s squared. F = ma = 2 x 3 = 6 N. Its weight on Earth is mg = 2 x 9.8 = 19.6 N, a different quantity.