Download OBJECTIVE 5 - Motion, Forces, and Energy

OBJECTIVE 5 - Motion, Forces, and Energy
Physics 1 – Introduction
http://www.youtube.com/watch?list=PL005B8C98C0D8AB59&v=pE3WhJjtxh8&feature=player_detailpage
*Physics units: http://www.cstephenmurray.com/onlinequizes/physics/solvingequations/physicsunits.htm
*Variables 1: http://www.cstephenmurray.com/onlinequizes/physics/solvingequations/variables1.htm
*Variables 2: http://www.cstephenmurray.com/onlinequizes/physics/solvingequations/variables2.htm
*Choose the correct equation:
http://www.cstephenmurray.com/onlinequizes/physics/solvingequations/choosinganequation.htm
*Moving variables pre-lesson:
http://www.cstephenmurray.com/onlinequizes/physics/solvingequations/prelessonmovingvariables.htm
*Moving variables: http://www.cstephenmurray.com/onlinequizes/physics/solvingequations/movingvariables.htm
Specific Heat
Specific heat: Cp, heat, measured in joules (J), required to raise the temperature of one gram of a substance by 1 oC;
it varies according to the substance and its state of matter; Cp of liquid water is about 4.18 J/ (goC)
Example: How much heat is required to increase the temperature of 15 grams of water from 20 oC to 25 oC?
Heat = mass x change in temp. x specific heat
Heat = 15g x (25 oC – 20 oC) x 4.18 J/ (g oC) = 313.5 J
Water phase diagram - temperature does not change during a phase change!
Physics 2 – Density & Specific Heat
http://www.youtube.com/watch?v=XuCul_jTOzg&list=PL005B8C98C0D8AB59&feature=player_detailpage
Physics 2A – Density & Specific Heat (exercise)
http://www.youtube.com/watch?list=PL005B8C98C0D8AB59&v=1yIbd2mdZ0w&feature=player_detailpage
Speed, Momentum, and Acceleration
Physics 4 – Motion, Velocity & Acceleration
http://www.youtube.com/watch?list=PL005B8C98C0D8AB59&v=4NADtMUsp2U&feature=player_detailpage
Motion: change in position over a certain amount of time.
Speed: rate at which an object moves.
Speed = distance/time
Velocity: describes speed in a given direction.
*Calculating speed 1: http://www.cstephenmurray.com/onlinequizes/physics/speedexercises/calculatingspeed1.htm
*Calculating speed 2: http://www.cstephenmurray.com/onlinequizes/physics/speedexercises/calculatingspeed2.htm
*Calculating speed 3: http://www.cstephenmurray.com/onlinequizes/physics/speedexercises/speed3.htm
*Calculating avg. speed 1: http://www.cstephenmurray.com/onlinequizes/physics/speedexercises/averagespeed.htm
*Calculating avg. speed 2: http://www.cstephenmurray.com/onlinequizes/physics/speedexercises/averagespeed2.htm
Momentum: tendency of an object to keep moving in the direction in which it is moving.
Momentum = mass x velocity
*Understanding momentum:
http://www.cstephenmurray.com/onlinequizes/physics/momentum/understandingmomentum.htm
*Momentum word problems: http://www.cstephenmurray.com/onlinequizes/physics/momentum/momentum.htm
Acceleration: change in velocity over change in time (positive acceleration – speeding up;
negative acceleration – slow down)
Acceleration = (velocityfinal – velocityinitial)/change in time
*Calculating acceleration 1: http://www.cstephenmurray.com/onlinequizes/physics/speedexercises/acceleration.htm
*Calculating acceleration 2: http://www.cstephenmurray.com/onlinequizes/physics/speedexercises/acceleration2.htm
*Calculating acceleration 3: http://www.cstephenmurray.com/onlinequizes/physics/speedexercises/acceleration3.htm
Physics 4A – Velocity & Acceleration (exercise)
http://www.youtube.com/watch?feature=player_detailpage&v=BWHUVDGGDIc&list=PL005B8C98C0D8AB59
Work and Power
Physics 5 – Work, Power & Simple Machines
http://www.youtube.com/watch?v=knYvIn3jxtU&list=PL005B8C98C0D8AB59&feature=player_detailpage
Energy: ability to move or change matter (do work); measured in Joules
Work: force acting over a distance; measured in Joules
Work = force x distance
Power: work transferred per time; measured in Watts
Power = work/time
Physics 5A – Work & Power (exercise)
http://www.youtube.com/watch?feature=player_detailpage&v=tojxIzys05U&list=PL005B8C98C0D8AB59
*Work and energy vocab: http://www.cstephenmurray.com/onlinequizes/physics/workandenergy/vocabch5no1.htm
*Work pre-lesson: http://www.cstephenmurray.com/onlinequizes/physics/workandenergy/workprelesson.htm
*Work problems: http://www.cstephenmurray.com/onlinequizes/physics/workandenergy/workproblems1.htm
*Power problems: http://www.cstephenmurray.com/onlinequizes/physics/workandenergy/powerproblems.htm
Simple Machines
A device that makes work easier in 3 ways:
1. increase the distance covered (pushing a box up a ramp)
2. decrease the force required (pulling out a nail with a crowbar)
3. change the rate at which work is done
*Identifying simple machines:
http://www.cstephenmurray.com/onlinequizes/physics/simplemachines/simplemachinematching.htm
Examples: inclined plane
lever
pulley
wheel and axle
wedge
screw
*Lever basics: http://www.cstephenmurray.com/onlinequizes/physics/simplemachines/leverbasics.htm
*Classes of levers: http://www.cstephenmurray.com/onlinequizes/physics/simplemachines/classesoflevers.htm
Efficiency: comparison between the work output (WO) and the work input (WI) of a machine.
work output
% Efficiency =
X 100
work input
Newton’s Laws
Physics 3 – Newton’s Laws
http://www.youtube.com/watch?list=PL005B8C98C0D8AB59&v=GCo0OMfpMZg&feature=player_detailpage
*Newton’s Laws: http://www.cstephenmurray.com/onlinequizes/physics/forces/Newtonslaws.htm
Force: a push or pull; needed to start or stop the motion of an object; measured in Newtons (N)
Net Force: the overall force on an object; must be greater than zero for motion; no motion occurs if net force is zero
(balanced)
An object will move in the direction of the net (unbalanced) force.
20 N
40 N
Net force = 40 N - 20 N = 20 N (right)
Resistance Force: a force that opposes motion; ex. friction.
Gravity: force that pulls objects in the universe toward each other
> Gravity allows objects to orbit (satellites orbit the earth, earth orbits the sun)
> Earth’s gravity is greater than moon’s gravity (earth is larger than moon) therefore, objects weigh more on
earth than
on moon (mass remains constant)
> Earth’s gravitational acceleration = 9.8 m/s
Weight: measures the force of gravity on an object; measured in Newtons.
Weight = mass x acceleration due to gravity
*Mass vs. weight: http://www.cstephenmurray.com/onlinequizes/physics/forces/MassVsWeight.htm
Inertia: the property of an object that resists a change in motion.
*Understanding inertia: http://www.cstephenmurray.com/onlinequizes/physics/forces/understandinginertia.htm
Newton’s Laws of Motion:
1. Law of inertia: objects at rest remain at rest and objects in motion remain in motion, unless acted upon by
an unbalanced force
Example: seat belts protect people’s bodies from continuing to move forward when a car stops abruptly
2. Force = mass x acceleration: force causes acceleration, while mass opposes acceleration
Example: if a person applies the same force, a baseball (which has less mass) will have more acceleration
than a bowling ball (which has a greater mass)
3. For every force, there is an equal but opposite force
Example: gas from rocket goes downward, rocket moves upward
*Newton’s Second Law: http://www.cstephenmurray.com/onlinequizes/physics/forces/secondlaw1.htm
Interactions of Waves
Wave: disturbance that transmits energy; caused by vibration
Transverse wave: vibration is perpendicular to wave direction
Longitudinal wave: vibration is parallel to wave direction
Amplitude: maximum distance from resting point (in absolute value)
Wavelength: distance between 2 adjacent crests or troughs
Frequency; f, wavelengths per time period; measured in Hertz (Hz = 1 wave/sec).
wave velocity = wavelength x frequency
Example: Waves
Interference: two waves occupy same space; form new wave
Type
Alignment of
Constructive
crests (wave A) with crests (wave B)
Destructive
crests (wave A) with troughs (wave B)
Result
add amplitudes (= larger amplitudes)
subtract amplitudes (= flat line)
Medium: substance (solid, liquid, gas) in which wave travels
Mechanical waves: waves that require a medium (ocean waves in water or sound waves through air or seismic waves
in earth)
Electromagnetic waves: waves that do not require a medium; can travel through a vacuum (empty space) at the
speed of light
Examples: visible light, radio waves, X-rays, microwaves
Resonance: two systems vibrating at the same frequency result in an increase in amplitude
Reflection: change in wave direction at boundaries of two unlike media
Example:
Normal: line perpendicular to surface
a
b
Law of Reflection:
Angle of incidence (a) = angle of reflection
(b)
Refraction: change in wave direction (bending) due to change of velocity as it passes through two unlike media
Example:
Normal
Air (fast)
Glass (slow)
Light wave passing from “fast” medium into “slow” medium bends toward the normal
Normal
Glass (slow)
Air (fast)
Light wave passing from “slow” medium into “fast” medium bends away from the normal.
Energy
Energy: ability to move or change matter (do work); measured in Joules
*Types of energy: http://www.cstephenmurray.com/onlinequizes/physics/workandenergy/typesofenergy.htm
*Energy vocab: http://www.cstephenmurray.com/onlinequizes/physics/workandenergy/vocabch5no3.htm
Potential Energy: energy of position (rock sitting on top of hill)
Gravitational Potential Energy = mass x gravity x height
Kinetic Energy: energy of motion (rock rolling down hill)
Kinetic Energy = ½ (mass x velocity2)
*Potential energy and kinetic energy pre-lesson:
http://www.cstephenmurray.com/onlinequizes/physics/workandenergy/EpEkprelesson.htm
Physics 6 – Kinetic & potential Energy
http://www.youtube.com/watch?list=PL005B8C98C0D8AB59&v=SZGnHuXYbfg&feature=player_detailpage
Physics 6A – Kinetic & Potential Energy (exercise)
http://www.youtube.com/watch?list=PL005B8C98C0D8AB59&v=Qvwd5_N0PoE&feature=player_detailpage
Physics 6B – KE & PE related
http://www.youtube.com/watch?feature=player_detailpage&v=O3hPS4m8WMs&list=PL005B8C98C0D8AB59
*Kinetic vs. potential energy:
http://www.cstephenmurray.com/onlinequizes/physics/workandenergy/kineticvspotentialenergy.htm
*Potential energy problems:
http://www.cstephenmurray.com/onlinequizes/physics/workandenergy/potentialenergyproblems.htm
*Kinetic energy problems:
http://www.cstephenmurray.com/onlinequizes/physics/workandenergy/kineticenergyproblems.htm
Energy Form
Chemical
Mechanical
Electrical
Sound
speed
Light
108 m/s
Solar
Heat (Thermal)
Description:
energy stored in molecules/chemical bonds
energy resulting from position or motion (Potential & Kinetic)
electron movement through a conductor
longitudinal waves cause vibration; increased temperature and the density of the medium increase
transverse electromagnetic wave; can polarize (separate) into parallel planes; speed of light = 3 x
sun-generated; provides most of Earth’s energy
due to particle vibration (kinetic energy of particles); transferred in 3 ways:
Natural Resource: substance that helps support life on Earth
Resource Type
Time to replace
Examples
Renewable
within a person’s lifetime
trees, wind
Nonrenewable
millions of years
oil, gas, coal
Inexhaustible
not used up
sun, wind, tides
Fossil fuels: substances made over many years from the remains of living things (oil, gas, coal)
Alternative fuels: energy sources other than fossil fuels
Examples: solar cells, wind turbines, ethanol from corn
Fuel
Fossil
Alternative
Common Disadvantages
nonrenewable, environmental pollution
not always practical, expensive, disposal issues
Law of Conservation of Energy
Law of Conservation of Energy: energy cannot be created or destroyed but it changes from one form to another
Examples: Electrical energy changes to light energy when a lamp is turned on. Chemical energy in a match
changes to light energy and heat energy when lit.
Heat
Temperature is a measure of the average kinetic energy of the particles in a substance.
Heat (measured in Joules) is the transfer of thermal energy between objects at different temperatures.
Heat always flows in the same direction: from the hotter object to the cooler object.
Method
Radiation
Conduction
Convection
Heat Transfer Process
electromagnetic waves (heat from Sun, fire, etc)
objects in contact (hot metal fork burns fingers)
currents (warm air rises, cool air sinks)
Circuits and Electricity
Physics 7 – Circuits
http://www.youtube.com/watch?list=PL005B8C98C0D8AB59&v=WeXCB55VkyQ&feature=player_detailpage
Physics 7A – Electricity (exercise)
http://www.youtube.com/watch?feature=player_detailpage&v=Dn08FrFFGRI&list=PL005B8C98C0D8AB59