2 Use your notes to solve the following: Thursday, 10/31Happy Halloween!Use your notes to solve the following:Find the weights of these objects: kg car kg baseballUpcoming Events:Open note quiz – Wednesday, 11/6Unit 4 Test – Wednesday, 11/12
3 Unit 4: Forces Free-Body Diagrams Vector ReviewA vector has magnitude and direction (ex. Velocity)The magnitude of the vector quantifies how large it is.Arrows are used to depict a vector (size and direction)Force is a vectorMagnitude – amount of force in Newtons (N)Direction is depicted with an arrow
4 Unit 4: Forces Free-Body Diagrams Free Body Diagrams are…Are a pictorial representation of forces acting on an object.Are used to show the magnitude and direction of all forces acting on an object.The size of the arrow reflects the size of the forceThe arrow shows the direction the force is actingForce is a vectorMagnitude – amount of force in Newtons (N)Direction is depicted with an arrow
5 Unit 4: Forces Free-Body Diagrams Steps for drawing Free-body diagramsReplace the object with a dot or box.Identify all the long-range forces acting on the object (ex. Gravity)Identify all the contact forces acting on the object.Remember that only something that is physically touching the object can apply a contact forcePossible types of contact forces – push, tension, normal, and friction
6 Unit 4: Forces Free-Body Diagrams Things to remember when working with force diagrams:Always follow all 3 stepsForce due to gravity acts on all objects and always points downForce arrows must originate from the dot, this means that you will never have an arrow pointing at the dot, always away from the dotSurfaces apply a normal force that is always perpendicular to the surface.