Fundamental Physics Concepts

Scalars and vectors are the building blocks of physics that you'll use constantly. Scalars like speed, distance and temperature only have size, whilst vectors like velocity, acceleration and weight have both size and direction - this difference is crucial for solving problems.

Speed-distance-time (SDT) graphs show you motion patterns at a glance. The gradient tells you acceleration by using Δy/Δx, straight lines mean constant speed, and horizontal lines show something is stationary. These graphs make complex motion simple to understand.

Newton's three laws govern all movement around us. The first law explains why you slide forward when a bus brakes - balanced forces keep things moving at constant speed. The second law gives you the formula a = F/m, connecting force, mass and acceleration. The third law states every action has an equal and opposite reaction, but remember these forces must act on different objects.

Quick tip: When calculating resultant force, simply subtract opposing forces $like 15N - 5N = 10N$ to find the net effect on an object's motion.

Motion, Forces and Energy Systems

Circular motion involves centripetal force acting at 90° to movement, creating constant speed but changing velocity. This explains everything from satellites orbiting Earth to cars turning corners - the speed stays the same, but direction constantly changes.

Weight calculations using W = mg connect mass and gravitational field strength. Remember that weight (measured in Newtons) differs from mass (measured in kg) - your mass stays constant, but your weight changes on different planets. Human reaction time affects driving safety, influencing both thinking distance and braking distance.

Energy stores and transfers show how energy moves through systems. Chemical energy in fuel converts to kinetic energy in moving cars, then to thermal energy in brakes. Understanding these transfers helps explain everything from renewable energy sources like solar cells and wind turbines to why fossil fuels are non-renewable.

Wave equations like v = fλ connect wave speed, frequency and wavelength, fundamental for understanding energy transmission from sources to Earth.

Remember: Stopping distance = thinking distance + braking distance, and factors like wet roads, worn tyres, or driver fatigue significantly increase both components.