Free Body Diagrams A Free Body Diagram (FBD) is a visual representation of all the forces acting on a single object FBDs are extremely powerful problem solving tools that bridge the gap between qualitative analysis and a quantitative mathematical representation

Drawing an FBD… A simple dot can be used to represent the object in question Identify the forces acting ON that object only Draw one arrow to represent each force acting ON the object – All arrows should be drawn from the dot or the center of the object – The arrows point in the direction of the force. – The length of the arrow represents the relative magnitude of the force…ie longer arrows = larger force

Example 1 Normal Force Weight/Force due to Gravity A lab cart resting on a worktop

Example 2 A lab cart moving with a constant velocity across a surface Normal Force Weight Applied Force friction

Example 3 A lab cart accelerating across a surface Normal Force Weight Applied Force friction

Example 3 A tetherball while swinging at a constant speed around a pole Weight Tension