Physics: Concepts and Applications
Core Concepts
Physics for Navik GD emphasizes mechanics and everyday applications: units and measurement (SI units), motion and Newton's laws, work, energy and power, gravitation, pressure and floatation, heat and temperature, sound, light (reflection and refraction), electricity and magnetism, and simple machines. Naval context helps: buoyancy, density, and pressure are especially relevant.
Traps to Watch
Questions test the difference between scalar and vector quantities, mass and weight, and speed and velocity. In optics, the direction of bending depends on whether light moves from a denser to a rarer medium. In electricity, series and parallel combinations give different equivalent resistances. In floatation, an object floats when its weight equals the buoyant force, not simply because it is light. Unit conversions (km/h to m/s by multiplying by 5/18) are a frequent trap.
Rule of Thumb
Use the definition-first approach: recall the exact definition and the SI unit before computing. For Archimedes' principle, the buoyant force equals the weight of displaced fluid.
Worked Example
A body of mass 10 kg is lifted 2 m. Find the work done (g = 10 m/s^2). Work = force x distance = (10 x 10) x 2 = 200 J. Note the unit is joules, not newtons, which is a common distractor.