AP Phys BAP Phys BTest ReviewTest Review

Kinematics and Newton’s Kinematics and Newton’s LawsLaws

4/28/20084/28/2008

OverviewOverview

Units and DimensionsUnits and Dimensions Scalars and VectorsScalars and Vectors

– 1-D, 2-D, and 3-D1-D, 2-D, and 3-D Particle KinematicsParticle Kinematics Newton’s Laws of MotionNewton’s Laws of Motion

– GravityGravity– FrictionFriction

Units and DimensionsUnits and Dimensions

Metric SystemMetric System ConversionsConversions Dimensional Dimensional

AnalysisAnalysis Order of Order of

Magnitude Magnitude EstimationsEstimations

Scalars and VectorsScalars and Vectors

Scalars: Magnitude Scalars: Magnitude onlyonly..

Vectors: Magnitude Vectors: Magnitude andand direction. direction.– Vectors componentsVectors components

Cartesian coordinatesCartesian coordinates TrigonometryTrigonometry

– Find the magnitude Find the magnitude of a vectorof a vector

v

vx

vy

Scalars and VectorsScalars and Vectors

Vector Addition and SubtractionVector Addition and Subtraction– Graphical Representation “Head to Graphical Representation “Head to

tail”tail”– Mathematical operationMathematical operation

Vector multiplicationVector multiplication– Dot ProductDot Product– Cross ProductCross Product

Particle KinematicsParticle Kinematics

Distance and DisplacementDistance and Displacement– Distance: lengthDistance: length– Displacement: length and directionDisplacement: length and direction

Speed and VelocitySpeed and Velocity– Speed: distance/timeSpeed: distance/time– Velocity: displacement/timeVelocity: displacement/time

AccelerationAcceleration– Change in speed (velocity)/timeChange in speed (velocity)/time

Particle KinematicsParticle Kinematics

GraphsGraphs– Distance vs. time Distance vs. time

graphs; slopegraphs; slope– Velocity vs. time Velocity vs. time

graphs; slope, graphs; slope, areaarea

Instantaneous Instantaneous vs. average vs. average valuesvalues

Particle KinematicsParticle Kinematics

Problem Solving StrategiesProblem Solving Strategies– Identify known quantitiesIdentify known quantities– Key words: at rest, constant speedKey words: at rest, constant speed

Free fall problemsFree fall problems– Acceleration due to gravity: 9.8 m/sAcceleration due to gravity: 9.8 m/s22

Use common sense!Use common sense!

Particle KinematicsParticle Kinematics

Equations of Equations of MotionMotion

Vf

Vi

a

t

d

x y

atvv if 2

2

1attvd i

advv if 222

Newton’s LawsNewton’s Laws

11stst law (Law of Inertia): An object at law (Law of Inertia): An object at rest stays at rest, and object in rest stays at rest, and object in motion stays in motion in a straight motion stays in motion in a straight line at a constant speed until acted line at a constant speed until acted on by an outside force.on by an outside force.– Inertia: Resistance of an object to Inertia: Resistance of an object to

changechange– Meaning: Things don’t speed up or Meaning: Things don’t speed up or

slow down without a reason.slow down without a reason.

Newton’s LawsNewton’s Laws

22ndnd Law: The acceleration of an object is Law: The acceleration of an object is proportional to the force on that object proportional to the force on that object and is inversely proportional to the mass and is inversely proportional to the mass of the object.of the object.– Meaning: The heavier something is, the Meaning: The heavier something is, the

more force it takes to achieve a certain more force it takes to achieve a certain acceleration.acceleration.

m

Fa

Newton’s LawsNewton’s Laws

33rdrd law: For every action, there is law: For every action, there is an equal and opposite reactionan equal and opposite reaction– All forces occur in pairs.All forces occur in pairs.– These forces cannot occur on the These forces cannot occur on the

same object.same object.

Newton’s LawsNewton’s Laws

Balanced vs. Unbalanced forces; Balanced vs. Unbalanced forces; EquilibriumEquilibrium

Free-Body DiagramsFree-Body Diagrams– Determining accelerationDetermining acceleration– Normal ForceNormal Force– Tension (pulleys)Tension (pulleys)– Friction (static and kinetic)Friction (static and kinetic)– Inclined Plane ProblemsInclined Plane Problems

Newton’s LawsNewton’s Laws

Circular ForceCircular Force– Radial vs. tangential Radial vs. tangential

accelerationacceleration– Centripetal force: an Centripetal force: an

unbalanced force unbalanced force Newton’s Law of Newton’s Law of

Universal Universal GravitationGravitation– Gives the Gives the

gravitational force gravitational force between two objects.between two objects.

r

vac

2

221

r

MGMFg