Forces and Vectors
Ever wondered why a magnet can move a paperclip without touching it? That's the difference between contact forces (like pushing a door) and non-contact forces (like magnetism, gravity, and electrostatic force).
Understanding scalars and vectors is crucial for your exams. A scalar only has size (magnitude) - like distance or temperature. A vector has both size and direction - like displacement or force. When you're walking to school, the distance you travel is scalar, but your displacement (straight-line distance from start to finish) is vector.
The resultant force is simply adding up all the forces acting on an object. If forces are balanced (resultant = 0), there's no acceleration - this is Newton's first law. Think of a book sitting on a table - gravity pulls down, the table pushes up, so it stays put.
Weight is the force gravity exerts on an object: W = mg. On Earth, every 1kg weighs about 10N, but on the moon, you'd weigh much less because g = 1.6 N/kg there!
Quick Tip: Remember that mass stays the same everywhere, but weight changes depending on the planet's gravity!
