88thth Grade Physical Science Grade Physical Science

Force and Motion Force and Motion Speed is how fast an object Speed is how fast an object

is moving.is moving.

Speed =Speed =

You can also use this You can also use this formula to find the distance formula to find the distance or time as needed.or time as needed.

Distance = Speed x TimeDistance = Speed x Time Time = Time =

Speed and velocity are very Speed and velocity are very similar and are often used similar and are often used interchangeably.interchangeably.

DistanceDistance

TimeTime

DistanceDistance

SpeedSpeed

Force and MotionForce and Motion

Velocity is the rate at which Velocity is the rate at which an object changes its an object changes its position.position.

Velocity = Velocity =

Speed and velocity are Speed and velocity are equal only if the distance an equal only if the distance an object travels is equal to its object travels is equal to its displacement (how far it is displacement (how far it is away from its original away from its original position).position).

Velocity has direction!Velocity has direction!

DisplacementDisplacement

SpeedSpeed

Force and MotionForce and Motion Acceleration is the rate at Acceleration is the rate at

which an object’s velocity which an object’s velocity changes.changes.

Acceleration = Acceleration =

Positive acceleration Positive acceleration values mean that an object values mean that an object is speeding up is speeding up

Negative acceleration Negative acceleration values mean that an object values mean that an object is slowing down.is slowing down.

Negative acceleration is Negative acceleration is often called deceleration.often called deceleration.

Change in VelocityChange in Velocity

TimeTime

Force and MotionForce and Motion

A force is a push or pull that starts, stops, or A force is a push or pull that starts, stops, or changes the direction of an object.changes the direction of an object.

Some examples of contact forces are gravity and Some examples of contact forces are gravity and friction.friction.

Some examples of non-contact forces are Some examples of non-contact forces are magnetism and electricity.magnetism and electricity.

Gravity keeps the planets in orbit around the sun.Gravity keeps the planets in orbit around the sun. Friction can slow down and stop objects in motion.Friction can slow down and stop objects in motion. Electricity and magnetism interact in motors and Electricity and magnetism interact in motors and

other devices.other devices.

Force and MotionForce and Motion Issac Newton stated three laws Issac Newton stated three laws

of motion that describe how of motion that describe how forces affect us.forces affect us.

Newton observed that an object Newton observed that an object at rest stays at rest until an at rest stays at rest until an outside force causes it to move. outside force causes it to move. (1(1stst Law of Motion) Law of Motion)

Force = Mass x AccelerationForce = Mass x AccelerationIn other words, Newton showed In other words, Newton showed that the motion of an object that the motion of an object changes, or accelerates, when changes, or accelerates, when a force acts on it. (2a force acts on it. (2ndnd Law of Law of Motion)Motion)

Newton observed that when one Newton observed that when one object exerts a force upon object exerts a force upon another object, the second another object, the second object exerts an equal and object exerts an equal and opposite force upon the first opposite force upon the first object. (3object. (3rdrd Law of Motion) Law of Motion)

Force and MotionForce and Motion

Forces can be balanced or unbalanced.Forces can be balanced or unbalanced. Unbalanced forces cause an object to start Unbalanced forces cause an object to start

moving (accelerate) but balanced forces do moving (accelerate) but balanced forces do not.not.

Work and Simple MachinesWork and Simple Machines

Work occurs when an object moves and a Work occurs when an object moves and a force acts on the object in the same force acts on the object in the same direction that it moves.direction that it moves.

Work = Force x DistanceWork = Force x Distance Power is the rate at which work is done.Power is the rate at which work is done. Power = Work / TimePower = Work / Time

Work and Simple MachinesWork and Simple Machines

A machine is a device that does work. Machines A machine is a device that does work. Machines do not increase the amount of work done, but they do not increase the amount of work done, but they do make work easier. do make work easier.

Machines make work easier by changing force or Machines make work easier by changing force or distance, or by changing the direction of the force. distance, or by changing the direction of the force.

There are three simple machines: the lever, the There are three simple machines: the lever, the pulley, and the inclined plane. pulley, and the inclined plane.

The wheel and axle, the wedge, and the screw are The wheel and axle, the wedge, and the screw are modifications of the three simple machines. modifications of the three simple machines.

A complex machine is a machine made up of two A complex machine is a machine made up of two or more simple machines. or more simple machines.

Work and Simple MachinesWork and Simple Machines

Work and Simple MachinesWork and Simple Machines Most machines multiply the force of your efforts.Most machines multiply the force of your efforts. The force applied to the machine is called the effort forceThe force applied to the machine is called the effort force The force opposing the effort force is the resistance force.The force opposing the effort force is the resistance force. The number of times that a machine multiplies an effort The number of times that a machine multiplies an effort

force is its mechanical advantage (M.A.).force is its mechanical advantage (M.A.). A machine with a M.A. of 2 doubles your effort force.A machine with a M.A. of 2 doubles your effort force. M.A. = Resistance Force / Effort ForceM.A. = Resistance Force / Effort Force The mechanical efficiency (M.E.) of a machine compares The mechanical efficiency (M.E.) of a machine compares

its work output with the work input.its work output with the work input. M.E. = Work Output / Work Input x 100%M.E. = Work Output / Work Input x 100% Because the work output is always less than the work Because the work output is always less than the work

input, the mechanical efficiency of a machine is always less input, the mechanical efficiency of a machine is always less than 100%.than 100%.

Work and Simple MachinesWork and Simple Machines

There are three kinds of levers.There are three kinds of levers. The M.A. of a lever is calculated by dividing The M.A. of a lever is calculated by dividing

the effort distance by the resistance the effort distance by the resistance distance.distance.

Work and Simple MachinesWork and Simple Machines

The M.A. of a wheel and axle is equal to the The M.A. of a wheel and axle is equal to the radius of the wheel divided by the radius of radius of the wheel divided by the radius of the axle.the axle.

Work and Simple MachinesWork and Simple Machines

The two main types of pulleys are fixed pulleys and The two main types of pulleys are fixed pulleys and movable pulleys.movable pulleys.

A fixed pulley is attached to a stationary structure. A fixed pulley is attached to a stationary structure. The M.A. is 1 because it does not multiply the effort force. The M.A. is 1 because it does not multiply the effort force.

It only changes the direction of the force.It only changes the direction of the force. A movable pulley is hung on a rope and hooked to a A movable pulley is hung on a rope and hooked to a

weight.weight. The M.A. is 2 because it doubles the effort force. It also The M.A. is 2 because it doubles the effort force. It also

changes the direction of the force.changes the direction of the force. A pulley system combines two or more pulleys.A pulley system combines two or more pulleys. The M.A of a pulley system is equal to the number of rope The M.A of a pulley system is equal to the number of rope

segments pulling up on the weight.segments pulling up on the weight.

Work and Simple MachinesWork and Simple Machines

EnergyEnergy

Energy is the ability to cause change or do Energy is the ability to cause change or do work.work.

There are five main types of energy: There are five main types of energy: mechanical, nuclear, chemical, mechanical, nuclear, chemical, electromagnetic, and thermal.electromagnetic, and thermal.

The mechanical energy of a moving object The mechanical energy of a moving object is called its kinetic energy. is called its kinetic energy.

The mechanical energy of an object due to The mechanical energy of an object due to its position is called its potential energy.its position is called its potential energy.

EnergyEnergy

EnergyEnergy Energy is constantly changing from one form to another.Energy is constantly changing from one form to another. As energy changes from one form to another, it is never created As energy changes from one form to another, it is never created

or destroyed.or destroyed. Many times it takes a whole series of energy conversions to do a Many times it takes a whole series of energy conversions to do a

certain job. certain job. For example, just to get the energy to make a piece of toast, For example, just to get the energy to make a piece of toast,

there are several energy conversions involved. there are several energy conversions involved. Chemical energy stored in coal is released as heat and light Chemical energy stored in coal is released as heat and light

energy when the coal is burned. energy when the coal is burned. The heat energy is used to produce steam and is changed into The heat energy is used to produce steam and is changed into

mechanical energy in a generator. mechanical energy in a generator. The generator converts mechanical energy into electric energy The generator converts mechanical energy into electric energy

that travels through power lines into your home.that travels through power lines into your home. When you use your toaster, that electric energy is again changed When you use your toaster, that electric energy is again changed

into heat energy. into heat energy.

Waves, Sound, and LightWaves, Sound, and Light

A wave is a disturbance that transfers energy A wave is a disturbance that transfers energy through matter or through space.through matter or through space.

Mechanical waves move through a medium which Mechanical waves move through a medium which can be a solid, liquid, or gas.can be a solid, liquid, or gas.

Sound waves, water waves, and earthquakes are Sound waves, water waves, and earthquakes are all mechanical waves.all mechanical waves.

Electromagnetic waves do not require a medium. Electromagnetic waves do not require a medium. Light waves are electromagnetic waves.Light waves are electromagnetic waves. Thus, light can travel through the vacuum of outer Thus, light can travel through the vacuum of outer

space but sound cannot.space but sound cannot.

Waves, Sound, and LightWaves, Sound, and Light

There are two types of mechanical waves, There are two types of mechanical waves, transverse waves and longitudinal waves.transverse waves and longitudinal waves.

Transverse waves have crests and troughs.Transverse waves have crests and troughs. Longitudinal waves have compressions and Longitudinal waves have compressions and

rarefactions.rarefactions.

Waves, Sound, and LightWaves, Sound, and Light

All waves have a wavelength, amplitude, frequency, and All waves have a wavelength, amplitude, frequency, and speed.speed.

On a transverse wave, the wavelength is the distance On a transverse wave, the wavelength is the distance between two consecutive crests or troughs.between two consecutive crests or troughs.

On a longitudinal wave, the wavelength is the distance On a longitudinal wave, the wavelength is the distance between two consecutive compressions or rarefactions.between two consecutive compressions or rarefactions.

The amplitude of a transverse wave is the vertical distance The amplitude of a transverse wave is the vertical distance between the line of origin and each crest or trough.between the line of origin and each crest or trough.

The frequency of a wave is the number of wavelengths that The frequency of a wave is the number of wavelengths that pass a point in a given amount of time.pass a point in a given amount of time.

The speed of a wave is equal to the frequency times the The speed of a wave is equal to the frequency times the wavelength.wavelength.

Waves, Sound, and LightWaves, Sound, and Light

Waves, Sound, and LightWaves, Sound, and Light

There are four kinds of wave interactions, There are four kinds of wave interactions, reflection, diffraction, refraction, and reflection, diffraction, refraction, and interference.interference.

Reflection occurs when a wave bounces off Reflection occurs when a wave bounces off a surface.a surface.

Waves, Sound, and LightWaves, Sound, and Light

The bending of a wave as a result of the The bending of a wave as a result of the interaction between a wave and the edge of interaction between a wave and the edge of an object is called diffraction.an object is called diffraction.

The bending of a wave as a result of a The bending of a wave as a result of a change in speed is called refraction.change in speed is called refraction.

Waves, Sound, and LightWaves, Sound, and Light

Waves, Sound, and LightWaves, Sound, and Light Light acts as a particle and as a wave.Light acts as a particle and as a wave. Light waves act like transverse waves.Light waves act like transverse waves. Light waves are called electromagnetic waves.Light waves are called electromagnetic waves. Electromagnetic waves are arranged in order of their wavelength and Electromagnetic waves are arranged in order of their wavelength and

frequency.frequency.

Waves, Sound, and LightWaves, Sound, and Light

Sound waves are longitudinal waves.Sound waves are longitudinal waves. The speed of sound waves depends on the The speed of sound waves depends on the

medium through which they move, not the source.medium through which they move, not the source. Temperature, elasticity, and density of the medium Temperature, elasticity, and density of the medium

all affect the speed of sound waves.all affect the speed of sound waves. When the temperature of the air increases, the When the temperature of the air increases, the

speed of sound increases.speed of sound increases. Sound waves move quickly through matter that is Sound waves move quickly through matter that is

elastic.elastic. Sound waves also move quickly through matter Sound waves also move quickly through matter

that is dense.that is dense.

The End The End

Remember to use your FCAT Science Remember to use your FCAT Science Reference Sheet!Reference Sheet!

Most of the equations you will need will be Most of the equations you will need will be on this sheet. Any others should be on this sheet. Any others should be provided in the questions themselves.provided in the questions themselves.

Be sure to spend enough time and effort on Be sure to spend enough time and effort on the short and extended response questions.the short and extended response questions.

Good luck!Good luck!