# 2011 P HYSICS S TUDY G UIDE By: Steph Rizzi. M EASRUMENT /U NITS Scientific Notation: -notation tool used for extreme magnitudes Examples: 1. 46600000.

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2011 P HYSICS S TUDY G UIDE By: Steph Rizzi

M EASRUMENT /U NITS Scientific Notation: -notation tool used for extreme magnitudes Examples: 1. 46600000 = 4.66 x 10 7 2. 0.00053 = 5.3 x 10 - 4 Metric Prefixes: A notation tool for measurements utilizing powers of ten

P REFIXES PrefixSymbolPower x10 Centi-C-2 Milli-M-3 Kilo-K3

O NE - DIMENSIONAL M OTION Displacement: Change in position Not the same as distance traveled Notation= = f - I Final position minus initial position

V ELOCITY 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:

A CCELERATION 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

G RAPHICAL D ISPLAY OF M OTION DISTANCE VS. TIME

G RAPHICAL D ISPLAY OF M OTION V ELOCITY VS. T IME

G RAPHICAL D ISPLAY OF M OTION A CCELERATION V S. T IME *horizontal lines have a slope of zero

F REE -F ALL M OTION 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. V i = -V f 3. V top =0 m/s G= 9.8 m/s 2

T WO -D IMENSIONAL M OTION 2 dimensional motion is really just tow 1D motion equations Now have Y= vertical displacement

S CALARS VS. V ECTORS Scalar- just a magnitude (amount) Vector- includes a magnitude AND a direction ScalarVector TemperatureForce MassWeight SpeedDisplacement DistanceVelocity AreaAcceleration VolumePressure Time Power Heat

R ELATIVE M OTION NameDiagramInferred givens Notes Launched horizontally from a height V ix =V i V iy =0 m/s Y is negative Launched from an angle to the same height Y= 0m V ix =V fx A x = 0 m/s 2 V fy = -V iy V fytop = 0 m/s t top = t /2 Use SOH CAH TOA V ix = V i cosθ V iy =V i sinθ Launched at an angle from a height Y= 0m V ix =V fx A x = 0 m/s 2 V fy = -V i y V fytop = 0 m/s t top = t /2 Y is negative Find V fy to find t Always true: A y = -9.8 m/s 2 V ix =V fx t is always positiveA x = 0 m/s 2

P ATHS OF A P ROJECTILE 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

F ORCE AND M OTION Newtons 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

I NERTIA 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

F ORCES 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

N ORMAL F ORCE 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

I NCLINE

N ET F ORCE P ROBLEMS 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 xs together to get Fnetx Add all ys to get Fnety 4. Create a right triangle 5. Calculate Fnet magnitude and the angle using SOH CAH TOA

M OMENTUM AND I MPULSE Momentum (p) Has a direction because it is a vector

R EAL W ORLD E XAMPLES Parachuting Football helmet padding Something hitting water Airbag

C ONSERVATION OF M OMENTUM Momentum is conserved for interactions between two objects in a closed system

NameDiagramNotes 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)

W ORK AND E NERGY 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 perpendicularNo work Object is at restNo work

S OLVING A W ORK P ROBLEM There is a specific work for every force of an object This includes Wnet= Fnet X Only one object= one X

K INETIC E NERGY

M ECHANICAL E NERGIES

C ONSERVATION OF M ECHANICAL E NERGY 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 energygravity Mechanical Advantage Work in = Work out No units Usually a decimal or a percent

T YPES OF E NERGY 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 K X 2 (J)

C IRCULAR M OTION 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

T ORQUE

R OTATIONAL E QUILIBRIUM

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