Forces and Vectors Fundamentals
Scalars have magnitude only (like speed), whilst vectors have both magnitude and direction (like velocity). Think of arrows - the longer the arrow, the bigger the vector's magnitude.
When dealing with objects, the centre of mass is where all the mass appears to be concentrated. For symmetrical shapes, it's right in the middle, but for irregular shapes, you'll need to use a plumb line to find it.
Forces come in two flavours: contact forces (where objects physically touch) and non-contact forces (acting at a distance through fields like gravitational, electrostatic, or magnetic). When an object is in equilibrium, all forces are balanced and the resultant force equals zero.
Hooke's Law governs elastic objects - they return to their original shape unless you've pushed them past their limit. The extension is proportional to the force applied, which is crucial for understanding springs and elastic materials.
Key Insight: Work done against friction always creates thermal energy, making objects heat up - that's why rubbing your hands together warms them up!
