Physics 4-1 Changes in Motion Physics 4-2 to 4-4 Newton's Laws. Compiled by Jack Graham 2013. Physics 4-1 Changes in Motion Force is a vector Free Body Diagrams (figure 4-4 a-f).
Compiled by Jack Graham 2013
Physics 4-2 Newton's First lawInertia An object at rest remains at rest. An object in motion continues in motion with constant velocity (constant straight line speed) unless the object experiences a net external force. IFF the net external force = 0 then its acceleration = 0.net external force vector sum of all forces acting on an object.
Physics 4-3 Newton's 2nd and 3rd Laws2nd Law Force is proportional to mass and acceleration F = ma3rd Law Forces always exist in pairs such that they are oppositely directed and equal in magnitude.These pairs are called “action-reaction pairs”.Action-reaction pairs are simultaneous.Each half of the action-reaction pair act on different objects.Field forces also exist in pairs.For A-R pairs ma = - MA
Everyday ForcesWeight: Me versus The Earth“Normal Force” = “N” Compression Resistance of molecular substancesat right angles to surface of objects in contact with each otherFriction Force proportional to “N”Static Friction standing still Fs = - F appliedKinetic Friction Fk = - µF applied so net Fn= F-Fkµs = Coefficient of Static Friction Fs,max/Fnµk = Coefficient of Kinetic Friction Fk/FnsoFf = - µFn
Assignment: All Section Reviews (Do right after you read them, please)Assignment after all reading: Read CBL Sensors ExperimentDo Problems: ALL Conceptual Questions, plus # 11, 13, 15, 21, 29, 39, 43