Energy!Energy!Notes – 30Oct2014Notes – 30Oct2014

Pappalardo – Science Gr8Pappalardo – Science Gr8

PE PE KE KE PE, PE, etc. etc. (copy)(copy)

Potential Energy (PE) Potential Energy (PE) = stored energy an = stored energy an object/material has due to its position, object/material has due to its position, condition, or chemical compositioncondition, or chemical composition

Think: stretched rubber band (Think: stretched rubber band (elastic PEelastic PE), ), height above ground (height above ground (gravitational PEgravitational PE), or the ), or the energy stored in chemical bonds (energy stored in chemical bonds (chemical PE chemical PE – – like in food!)like in food!)

Kinetic Energy (KE)Kinetic Energy (KE) = the energy of moving = the energy of moving objectsobjects

Depends on MASS and SPEED/VELOCITYDepends on MASS and SPEED/VELOCITY

Like momentum, it can be transferred between Like momentum, it can be transferred between objectsobjects

Think: Newton’s Cradle, bowling, car crashesThink: Newton’s Cradle, bowling, car crashes

Roller Coasters Roller Coasters (fun)(fun)

Roller Coasters Roller Coasters (copy diagram)(copy diagram)

GPEGPE(copy diagram)(copy diagram)

PendulumsPendulums(copy diagram)(copy diagram)

Springs & Rubber Springs & Rubber BandsBands

(copy diagram)(copy diagram)

Newton’s Laws Newton’s Laws (again) (again) (copy)(copy)

Newton’s 1Newton’s 1stst Law of Motion: Law of Motion: the law of the law of

inertiainertiaObjects at rest tend to stay at rest…Objects at rest tend to stay at rest…

Objects in motion tend to stay in motion (in a Objects in motion tend to stay in motion (in a straight line, at a constant speed)…straight line, at a constant speed)…

UNLESS UNLESS outside forces act on the object (a push, outside forces act on the object (a push, a pull, gravity, friction, air resistance, etc.)a pull, gravity, friction, air resistance, etc.)

Newton’s 2Newton’s 2ndnd Law of Motion: Law of Motion: F = maF = maForce (Force (NewtonsNewtons) = Mass () = Mass (kgkg) x Acceleration () x Acceleration (m/sm/s22))

The more massive something is, the more force it will The more massive something is, the more force it will take to accelerate it in any direction!take to accelerate it in any direction!

Think: it takes more force to stop or start a real car Think: it takes more force to stop or start a real car than it does to play with a toy car!than it does to play with a toy car!

Newton’s Laws Newton’s Laws (again) (again) (copy)(copy)

Newton’s 3Newton’s 3rdrd Law of Motion: Law of Motion: Action & ReactionAction & Reaction

For every action, there is an equal – For every action, there is an equal – but opposite – reactionbut opposite – reaction

Think: pushing off a skateboard, Think: pushing off a skateboard, hitting a ball with a baseball bat, hitting a ball with a baseball bat, Teddy & Matthew or Nat & Lowen on Teddy & Matthew or Nat & Lowen on scooters scooters

Work Work (copy)(copy)

WorkWork is done only when a force is exerted over a is done only when a force is exerted over a distancedistance

Think: lifting books up, pushing a cart, pulling on a Think: lifting books up, pushing a cart, pulling on a wagonwagon

WorkWork ( (JoulesJoules) = ) = ForceForce ( (NewtonsNewtons) x ) x DistanceDistance ((metersmeters))

PowerPower is the amount of work done in a period of is the amount of work done in a period of timetime

Think: lifting weights quickly instead of slowlyThink: lifting weights quickly instead of slowly

Power Power ((WattsWatts) = ) = WorkWork ( (JoulesJoules) ÷ ) ÷ TimeTime ( (SecondsSeconds))

Simple Machines Simple Machines (copy)(copy)

Inclined PlaneInclined Plane = a slope that does not move (ramp) = a slope that does not move (ramp)

WedgeWedge = two sloping sides that meet at a point (axe = two sloping sides that meet at a point (axe blade)blade)

ScrewScrew = inclined plane wrapped around a cylinder = inclined plane wrapped around a cylinder (screw)(screw)

Wheel & AxleWheel & Axle = a wheel on a shaft, or axle (steering = a wheel on a shaft, or axle (steering wheel)wheel)

PulleyPulley = a rope that fits into a grooved wheel (used to = a rope that fits into a grooved wheel (used to raise and lower flags, for example)raise and lower flags, for example)

Simple Machines Simple Machines (copy)(copy)

LeverLever = rigid bar that turns around a fixed = rigid bar that turns around a fixed [fulcrum] point [fulcrum] point

11stst Class: Class:Fulcrum in the middle between the input & output forcesFulcrum in the middle between the input & output forces

Think: seesaws, pliers, oars, soda can tabsThink: seesaws, pliers, oars, soda can tabs

22ndnd Class: Class:Output force is between the input force and fulcrumOutput force is between the input force and fulcrum

Think: wheelbarrows, nutcrackers, bottle openersThink: wheelbarrows, nutcrackers, bottle openers

33rdrd Class: Class: Input force is between the fulcrum and output forceInput force is between the fulcrum and output force

Think: shovels, brooms, fishing rods, baseball bats, Think: shovels, brooms, fishing rods, baseball bats, toothbrushes, tweezers, golf clubs, rakes, human toothbrushes, tweezers, golf clubs, rakes, human forearmsforearms

Compound Compound Machines Machines (copy)(copy)

Compound MachinesCompound Machines = two or more simple = two or more simple machines working togethermachines working together

Think: Think: GearsGears (wheel & axle with teeth) (wheel & axle with teeth)

Think: Think: pencil sharpeners (gears, levers, wedges)pencil sharpeners (gears, levers, wedges)

Scissors (wedges, levers) Scissors (wedges, levers)

Axes (wedges, levers)Axes (wedges, levers)

Roller coasters, Ferris wheels, bicyclesRoller coasters, Ferris wheels, bicycles