2 What is FORCE? A push or pull on an object Causing resting objects to moveCausing moving objects to accelerate
3 Two Main Force Types Balanced Forces Unbalanced Forces Two Forces Opposite directionsBoth are equal in valueNo movement (stationary)Unbalanced ForcesTwo ForcesOne greater than the otherOpposite directionsMovement
5 1st Law of Motion The Law AKA Objects at rest remain at rest or objects in motion remain in motion unless acted on by a forceAKALaw of INERTIA
6 1st Law of MotionInertia—force that is resistant to the direction of motionConcept—unbalanced forcesEx:inertia belts (seat belts)Space ships going through space
7 2nd Law of Motion The Law Concept AKA The acceleration of a body depends on the ratio of the acting force to the mass of the bodyConceptUnbalanced forcesAKAThe force formula
8 F= force (unit = Newton) a= acceleration (unit m/s2 Force FormulaForce = mass * accelerationF= m*aF= force (unit = Newton)m= mass (unit = kg)a= acceleration (unit m/s2
9 Force Example Problems #1 How much force is needed to accelerate a 500-kg car at a rate of 4 m/s/s?#2 A 50-kg object is accelerating at a rate of 2 m/s/s, what is the force that caused this acceleration?
10 3rd Law of Motion The Law Concept Ex Remember, forces are equal For every action there is an equal but opposite reactionConceptBalanced ForcesExStationary ObjectsRockets being launchedRemember,forces are equalbut opposite
11 Applying the 3rd LawIf Rico kicked a ball with 100-N of force, how much force did the ball exert on Rico?
13 What is Friction? Is a force that resist motion and can cause heat Allows us to walk, drive a car, play sportsLubricants help reduce friction
14 4 Types of Friction Rolling Friction Static Friction Fluid Friction Friction acting on objects that are rollingEx: car tiredFluid FrictionFriction acting on objects going through a fluidFluid—liquid or gasEx: swimming or air resistanceStatic FrictionFriction force on stationary objectsEx: book sitting on deskSliding FrictionFriction acting on objects sliding over a surfaceEx: pushing a box