Physics Exam 1 Group 5B

Physics Exam 1 Group 5B

1. Chapter 2:Motion, Forces and Newton's Laws

   • Position & Displacement
     • Position: location relative to the origin or reference point Displacement: change in object's position (shortest distance)
       • displacement=final-initial
   • Speed & Velocity
     • Velocity: vector that measures how fast AND direction it goes
       • average velocity= displacement/time
       • velocity vs time graphs
     • Average Speed= distance traveled/time of trip
       • distance vs. time graphs
   • Acceleration
     • nonzero acceleration changes an object's state of motion
       • average acceleration= velocity/ time
   • Newton's First Law
     • inertia
       • object in motion will stay in motion while an object at rest will stay at rest
       • inertia: measure of an object's resistance to change in its motion; depends on its mass (SI unit is kg)
   • Newton's Second Law
     • link between motion and forces
       • multiple forces act on an object at one time; use newtons (N)as the SI unit
       • many applications
       • force= mass*acceleration
   • Newton's Third Law
     • where forces come from

2. Chapter 1: Introduction

   • Problem Solving Techniques
     • KUDOS method
       • K=known; U=unknown; D=definition(formula); O=output(calculations); S=substantiation(check it)
     • Types of problems
       • 1. Quantitative Problems 2. Concept Checks 3. Reasoning & Relationship problems (Identify what important might be "missing"
   • Scientific Notation & Significant Figures
     • Shorthand of writing very large and/or small numbers
     • Significant Figures
       • 1. Nonzero digits ARE significant 2. Final ending zeros written to the right of the decimal ARE significant 3. Decimals that are placeholders are NOT significant 4. Zeros written between digits ARE significant
     • Round numbers at the VERY end
   • Units Conversions & Dimensions
     • Dimensions: basic types of quantites that can be measured or computed
       • Unit: Standard amount of a dimensional quantity
         • EXAMPLES: kg,m,s
       • EXAMPLES: Length, Time, Mass, Electric Current, Temperature
       • Dimensional Analysis: used to check problems
         • Use: L for length, T for time, M for mass
   • Vectors
     • Written as an arrow and length mean magnitude and direction means direction it would be on a coordinate system
     • use trig. to find the sides and/or angle (cosine and sine)
     • to add vectors, tip-to-tail so A+B=C

3. Chapter 3:Forces and Motion in One Dimesions

   • Constant Acceleration (Equations of Motion)
     • velocity final x=velocity initial x+ (acceleration*time)
     • x= (velocity initial x* time)+ 1/2*acceleration*time squared
     • velocity final squared= velocity initial squared +2*acceleration*x
     • force= mass*acceleration
   • Normal Forces & Weight
     • normal force; perpendicular to plane of contact
     • weight is mass*gravity
   • Free Body Diagram
     • shows all forces acting on each object in a problem
   • Free Fall (1D motion)
     • under the influence of gravity (+ or- 9.8 meters per second squared)
       • velocity final= velocity initial + acceleration*time
       • x= velocity initial*time+ 1/2*acceleration*time squared
       • velocity finial squared= velocity initial squared+ 2*acceleration*x
   • Newton's Second Law Applications (Transmitting forces)
     • apparent weight
       • a<0; N=mg+ma (apparent weight is greater than true weight) (downward motion)
       • a<0; N=mg-ma (apparent weight is less than true weight) (upward motion)
       • a>0; N=mg+ma (apparent weight is greater than true weight)(upward motion)
       • a>0; N=mg-ma (apparent weight is less than true weight) (downward motion)
     • friction
       • kinetic friction= force kinetic* normal force= mass*acceleration
       • static friction= force static* normal force
       • no units
     • tension
       • ideal tension is zero
       • use free body diagram to find tension