2011 PHYSICS STUDY GUIDEBy: Steph Rizzi

MEASRUMENT/UNITS

Scientific Notation: -notation tool used for extreme magnitudesExamples:1. 46600000 = 4.66 x 107 2. 0.00053 = 5.3 x 10-4

Metric Prefixes: A notation tool for measurements utilizing

powers of ten

PREFIXES

Prefix Symbol Power x10

Centi- C -2

Milli- M -3

Kilo- K 3

ONE-DIMENSIONAL MOTION

Displacement: “Change in position” Not the same as distance traveled Notation=

= f-I

Final position minus initial position

VELOCITY

Velocity (v): “Change in position over change in time” Not the same as speed Two basic velocities:

Average Instantaneous (initial and final)

Units of velocity: meters per second (m/s) Velocity has a direction Equation:

ACCELERATION

Acceleration (a) “change in velocity over change in time” Acceleration has a direction- it can be positive or

negative Negative acceleration means you are slowing down

Equation

GRAPHICAL DISPLAY OF MOTIONDISTANCE VS. TIME

GRAPHICAL DISPLAY OF MOTIONVELOCITY VS. TIME

GRAPHICAL DISPLAY OF MOTIONACCELERATION VS. TIME

*horizontal lines have a slope of zero

FREE-FALL MOTION

Any motion of a body where gravity is the only or dominant force acting upon it, at least initially

Things that affect free fall Air resistance Elevation Where you are in the universe

Tips, Tricks, and Hints for Free Fall “same height” or “original position”

1. 2. Vi= -Vf

3. Vtop=0 m/s G= 9.8 m/s2

TWO-DIMENSIONAL MOTION

2 dimensional motion is really just tow 1D motion equations

Now have Y= vertical displacement

SCALARS VS. VECTORS

Scalar- just a magnitude (amount) Vector- includes a magnitude AND a direction

Scalar Vector

Temperature Force

Mass Weight

Speed Displacement

Distance Velocity

Area Acceleration

Volume Pressure

Time

Power

Heat

Vector Addition Finding the resultant vector (sum/final)

Colinear- in a line *Add vectors “head to tail”

RELATIVE MOTIONName Diagram Inferred

givensNotes

Launched horizontally from a height

Vix=Vi

Viy=0 m/sY is negative

Launched from an angle to the same height

Y= 0mVix=Vfx

Ax= 0 m/s2

Vfy= -Viy

Vfytop= 0 m/sttop= t/2

Use SOH CAH TOAVix= Vi cosθViy=Visinθ

Launched at an angle from a height

Y= 0mVix=Vfx

Ax= 0 m/s2

Vfy= -ViyVfytop= 0 m/sttop= t/2

Y is negativeFind Vfy to find t

Always true: Ay= -9.8 m/s2 Vix=Vfx

t is always positive Ax= 0 m/s2

PATHS OF A PROJECTILE

Projectile- An object falling over a distance above the

surface of a massive body “free falling with a horizontal velocity” Projectiles follow a parabolic path

FORCE AND MOTION

Newton’s Laws: 1. an object in motion or at rest will remain in

motion or at rest, unless acted upon by an outside force

2. F= ma, force is equal to mass times acceleration

3. For every action force, there is an equal and opposite reaction force

INERTIA

“The tendency of all mass to maintain its state of motion” When mass increases, so does inertia

Equilibrium Fnet (total)= N

Constant speed only means equilibrium if its in a straight line= constant velocity= no acceleration= no force

Gravity Law of universal Gravitation

FORCES

Friction: A force that resists motion of one object over (or

through) another object Two types:

1. Static Friction- force of friction between two surfaces at rest relative to one another

2. force of friction between two surfaces in motion relative to one another

NORMAL FORCE

“perpendicular force” Always perpendicular to the surface Always matches the force exerted perpendicular

to the surface unless the max normal force is reached in which case the surfaces will falter

INCLINE

NET FORCE PROBLEMS

Steps To Solve: 1. Draw a diagram

Forces on a “free body” 2. Final all x and y compononents 3. Find Fnetx and Fnety

Add all x’s together to get Fnetx Add all y’s to get Fnety

4. Create a right triangle 5. Calculate Fnet magnitude and the angle using

SOH CAH TOA

MOMENTUM AND IMPULSE

Momentum (p) Has a direction because it is a vector

REAL WORLD EXAMPLES

Parachuting Football helmet padding Something hitting water Airbag

CONSERVATION OF MOMENTUM

Momentum is conserved for interactions between two objects in a closed system

Name Diagram Notes

Inelastic -sound-energy is lost-most common

Perfectly inelastic -energy is lost-sound-real-world

Elastic -energy is conserved-no sound-not real-world (ideal)

WORK AND ENERGY

Work: W= Fd In units of joules

Situations

Force in the same direction as X

Positive work

Force in the opposite direction as X

Negative work

Force is perpendicular No work

Object is at rest No work

SOLVING A WORK PROBLEM

There is a specific work for every force of an object

This includes Wnet= FnetX Only one object= one X

KINETIC ENERGY

MECHANICAL ENERGIES

CONSERVATION OF MECHANICAL ENERGY According to the law of conservation of mechanical

energy, in an isolated system, that is, in the absence of non-conservative forces like friction, the initial total energy of the system equals to the total energy of the system. Simply stated, the total mechanical energy of a system is always constant (in case of absence of non-conservative forces). For instance, if a ball is rolled down a frictionless roller coaster, the initial and final energies remain constant. Conservative forces are those that don't depend on the path taken by an object. For example, gravity, spring and electrical forces are examples of mechanical energy

Mechanical Advantage Work in = Work out No units Usually a decimal or a percent

TYPES OF ENERGY Energy is the ability to do work

Potential energy Stored energy

Gravitational PE- energy stored in an object at a height above a gravitational source (earth) PE= mgh (J)

Elastic PE- energy stored in a compressed or stretched spring PEe= ½ KX2 (J)

CIRCULAR MOTION

t for 1 revolution is called a period T= the amount of time for one revolution in

seconds Centripetal Acceleration Centripetal force- the force that causes

circular motion by pushing or pulling an object towards the center

TORQUE

ROTATIONAL EQUILIBRIUM