Contact & Non-contact Forces

Forces are simply pushes or pulls that act on objects, measured in Newtons and always having both size and direction (making them vector quantities). Think of forces as invisible hands constantly pushing and pulling everything around you.

Non-contact forces work their magic without objects actually touching each other. The three main ones you'll encounter are gravitational force (like Earth pulling you down), magnetic force (like magnets attracting metal), and electrostatic force (like when your hair sticks to a balloon after rubbing it).

Contact forces only happen when objects are physically touching. These include friction (which stops you slipping on ice), tension $the force in a rope when you're playing tug-of-war$, and resistance (like air resistance slowing down a falling parachute).

Key Insight: When contact forces act between two objects, Newton's Third Law kicks in - both objects feel the same size force but in opposite directions. So when you push a wall, it pushes back on you with equal force!