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Motion & Its Applications. Forces & Free Body Diagrams. Definitions. Force: A push or a pull that is a vector quantity. Has magnitude and direction . Force of Gravity: The force of attraction between ANY two objects with mass. Only “felt” when one object has tremendous mass.
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Motion & Its Applications Forces & Free Body Diagrams
Definitions • Force: A push or a pull that is a vector quantity. • Has magnitude and direction. • Force of Gravity: The force of attraction between ANY two objects with mass. • Only “felt” when one object has tremendous mass. • Normal Force: Force applied by a surface to an object, opposite to gravity.
Friction: A force that is present and opposite in direction to motion (or attempted motion). • Two types: • Static Friction: Force that prevents an object from moving. • Kinetic Friction: Force that acts against motion. • Air Resistance: Frictional force against an object moving through air. • Tension: Force exerted by strings, ropes, etc. • Applied Force: General name for any contact force.
Units of Force • Force is measured in a unit called Newtons (N). • Named after Sir Isaac Newton.
Free-Body Diagrams (FBDs) • Diagrams that show all forces acting on an object. • All forces are to be drawn from the centre of mass of the object.
Eg.1: Draw an appropriate FBD for each situation below. • A textbook is resting on top of a desk. • A heavy block is being pulled horizontally by a rope. • A car is driving forward with an applied force of 200N, frictional force of 200N, gravitational force of 20000N and normal force of 20000N.