Science Science BenchmarkBenchmark 33

ReviewReviewMotion, Laws of Motion, Motion, Laws of Motion,

Machines, Work, Machines, Work, Power, Energy, Energy Power, Energy, Energy

Transformations Transformations

MotionMotion In order for there to be motion In order for there to be motion an object must move in relation to an object must move in relation to

reference pointsreference points

SpeedSpeed How much time it takes for an object How much time it takes for an object

to move a certain distanceto move a certain distance Formula v= d/t Formula v= d/t Measured in m/s or km/hr etc Measured in m/s or km/hr etc If you know both speed and direction If you know both speed and direction

then you know ----then you know ----

Velocity Velocity

AccelerationAcceleration The RATE at which The RATE at which velocityvelocity CHANGES CHANGES All these are accelerationAll these are acceleration : : Going fasterGoing faster Going slowerGoing slower TurningTurning

This is why planets are accelerating – This is why planets are accelerating – they are in a constant turn to form their they are in a constant turn to form their

orbit.orbit.

Laws of MotionLaws of Motion 11stst - inertia – objects want to keep - inertia – objects want to keep

doing what ever they are doingdoing what ever they are doing Books fly on floor when bus stopsBooks fly on floor when bus stops You move forward when your parents You move forward when your parents

slam on the car brakesslam on the car brakes

Laws of MotionLaws of Motion 22ndnd – acceleration – f=ma – acceleration – f=ma

A runner speeds up at the end of a raceA runner speeds up at the end of a race A car slows down because they ran out A car slows down because they ran out

of gasof gas It takes more force to stop a bus than a It takes more force to stop a bus than a

bicyclebicycle

To change acceleration – lower mass or To change acceleration – lower mass or use more forceuse more force

Laws of MotionLaws of Motion Remember :Remember :

Mass is the amount of matter in an Mass is the amount of matter in an objectobject

Weight is a measure of the pull of Weight is a measure of the pull of gravity on an objectgravity on an object

Laws of MotionLaws of Motion 33rdrd – action and reaction – equal and – action and reaction – equal and

opposite!!opposite!! When you jump down hard on a When you jump down hard on a

trampoline you will go high in the airtrampoline you will go high in the air When a rocket is fired the gases push When a rocket is fired the gases push

downward causing the rocket to go downward causing the rocket to go upwardupward

MachinesMachines There are six simple machines:There are six simple machines: 1. Lever1. Lever

11stst class class

22ndnd class class

33rdrd class class

MachinesMachines 2. wheel and axle2. wheel and axle

MachinesMachines 3. wedge3. wedge

MachinesMachines 4. screw4. screw

MachinesMachines 5. inclined plane5. inclined plane

MachinesMachines 6. pulley6. pulley

WorkWork Work is using a force to move an Work is using a force to move an

object object in the directionin the direction of the force of the force

Formula w=fdFormula w=fd Measured in joules (J)Measured in joules (J)

PowerPower How much work is done in a certain How much work is done in a certain

period of time.period of time. The The fasterfaster something does work the something does work the

more power it has!! (less time)more power it has!! (less time)

Formula P=w/tFormula P=w/t Measured in watts (w)Measured in watts (w)

EnergyEnergy

Energy is the ability to do Energy is the ability to do work or to make a change.work or to make a change.

There are two main There are two main categories of energy:categories of energy:PotentialPotentialKineticKinetic

Potential EnergyPotential Energy

Potential Energy is stored Potential Energy is stored energy.energy.

Food roller coasterFood roller coaster

Kinetic EnergyKinetic Energy Kinetic Energy is energy of Kinetic Energy is energy of

motionmotion

Energy Energy TransformationsTransformations

Energy is changed from one Energy is changed from one form to another but none form to another but none can be created or destroyed!can be created or destroyed!

Match – chemical

to thermal

Energy Energy TransformationsTransformationsFood – chemical

to mechanical

Energy Energy TransformationsTransformationsFood – chemical

to mechanical

Chemical Chemical ReactionsReactions

Remember the only true proof that a chemical reaction has taken place isthe formation of a new substance with new properties!!!

Chemical Chemical FormulaFormula

2Ca + O2 2CaO

Remember to count atoms to see if balanced!

Reactants Product

Good Luck!!!!Good Luck!!!!

Read well !!!!