PHYS1171 Lecture Notes - Lecture 2: Contact Force, Friction, Net Force
Document Summary
Weight force: newton"s law of gravitation- two bodies are attracted to each other by a force which is proportional to their masses and inversely proportional to the square of their separation. Masses = m1 and m2, g is a small constant, r = radius of earth (approx. Otherwise can be written as f = mg. Normal force: contact force- when you push against a wall and it pushes back . In physics, we resolve this contact force into components perpendicular and parallel to the surface of each body: By "normal" we don"t mean "regular" or "usual", rather we mean "perpendicular". The normal force, by definition, is perpendicular to the surface of the object. We use the symbol "n" to represent the normal force. Warning: you may have already noticed that "n" has been used in two ways. It represents the normal force, and it represents the unit of force (the newton).
