OBJECTIVE 5:THE STUDENT WILL DEMONSTRATE AN UNDERSTANDING OF MOTION, FORCES, AND ENERGY.

Basic Physics

Knows concepts of force and motion evident in everyday life.

Motion and Forces

Calculate speed, momentum, acceleration, work, and power in systems such as in the human body, moving toys, and machines.

Investigate and describe applications of Newton's laws such as in vehicle restraints, sports activities, geological processes, and satellite orbits.

Investigate and demonstrate [mechanical advantage and] efficiency of various machines such as levers, motors, wheels and axles, pulleys, and ramps.

Equations There are many equations you need to

know how to use. You will get a formula sheet with

constants. Be sure you know how to use it and are familiar with it.

Speed and Velocity How fast you change your position.

Units: t’s

up. Speed & velocity: m/s or cm/s or

km/hr Distance: m or cm or km Time: seconds (s) or hours (h)

Acceleration Acceleration is the rate of change of

velocity. It occurs when an object changes its

speed, its direction or both.

Units: Acceleration: m/s/s or m/s2

Velocity: m/s Time: s

Force Force is a push or pull that makes things

move (accelerate). This is Newton’s second law and the force is the net force.

Units: Force: Newtons (N) sometimes (n) Mass: kg Acceleration: m/s/s or m/s2

Newton’s First law of Motion An object in motion will stay in motion

and an object at rest will stay at rest unless acted upon by an external force.

A body persists in a state of uniform motion or of rest unless acted upon by an external force.

A body keeps doing what its doing unless forced to change.

AKA: the law of inertia.

Newton’s Second Law of Motion:

Force = mass x acceleration (this is a formula) Force equals mass times acceleration. net F = ma (formula sheet) AKA: F = ma With equal force…

a smaller mass object will accelerate at a large rate a big mass will accelerate at a small rate.

With equal masses… a larger force will accelerate it at a faster rate a small force will accelerate it at a smaller rate.

Weight You use Newton’s second law to calculate

something’s weight. The acceleration you would use is the

acceleration due to gravity; 9.8 m/s/s This is given to you on the formula sheet.

Weight = mass (in kilograms) x 9.8 m/s/s

Your weight would be in Newtons (N)

Newton’s Third Law of Motion: For every action there is an equal and

opposite reaction. AKA: Action – Reaction Law Action – Reaction Pairs.

Action: Joe hits Jack Reaction: Jack hits Joe Action: Bob pulls on box Reaction: Box pulls

on Bob Action: Earth pulls on Moon Reaction: Moon

Pulls on Earth

Gravity The pull of gravity depends on the size of the

objects (masses) and the distance between their centers.

This is explained by Newton’s Universal Law of Gravity. There is gravity between all objects in the universe.

Increasing the masses of one or both objects increases the force between them.

Increasing the distance between their centers, decreases the force of gravity (by a square).

Gravity and Circles Objects travel in a circle because

something holds it in orbit. This force is the pull of gravity. It is caused by the two objects in

question and the distance between them.

The pull of gravity is everywhere.

Momentum, p Momentum is moving mass. Momentum is mass times its velocity. Momentum, p, is measured in either:

kg m/s or g cm /s There is a formula for momentum.

Momentum Momentum is a concept of moving mass.

Units: Momentum: kg m/s or g cm/s Mass: kilograms (kg) or grams (g) Velocity: m/s or cm/s

Conservation of Momentum The total momentum before equals the

total momentum after. In dealing with momentum, directions

matter.

Conservation of Momentum The total momentum before a happening or

collision equals the total momentum after. You find the mv of each object before a

collision and the mv of each object after and they must be equal.

Momentum is a vector so its direction matters. The direction of the momentum is the same direction as its velocity.

They like momentum problems.

Knows the impact of energy transformations in everyday life.

Energy

Describe the law of conservation of energy. Investigate and demonstrate the

movement of heat through solids, liquids, and gases by convection, conduction, and radiation.

Investigate and compare economic and environmental impacts of using various energy sources such as rechargeable or disposable batteries and solar cells.

Convection A form of heat transfer through liquids

and gases (fluids). Heat is transferred by currents in the

fluids. Heat moved by fluid motion.

Conduction Heat transferred by vibrating

neighboring molecules. Heat transferred through solids. Heat moves from hot to cold.

Radiation Heat transferred by waves. Heat from our Sun reaches us through

waves.

Work, W Work is defined as force acting over a

distance. The force must move the object. There is a formula for work. Work, W , is measured in Joules, J.

Work Work is force acting over a distance. The

force must move the object.

Units: Work Joules (J) sometimes (j) Force: N Distance: m

Kinetic Energy Energy of motion. If an object is moving it has kinetic

energy. There is a formula for kinetic energy. Energy is measured in Joules, J.

Kinetic Energy Energy due to motion.

Units: KE: Joules (J) Mass: kg Velocity: m/s

Potential Energy Potential energy is stored energy. For TAKS, It is energy due to an object’s

height. There is a formula for potential energy. Energy is measured in Joules, J. Changes in potential energies are

important.

Gravitational Potential Energy

Energy due to its position and the pull of gravity.

Units: PE: Joules (J) Mass: kg Acceleration due to gravity: 9.8 m/s/s Height: m

Conservation of Energy The total energy before equals the total

energy after. Energy can change forms. Work is a form of energy.

Conservation of Energy Energy must be accounted for. Energy can change forms from Potential

Energy to Kinetic Energy and back again. The total amount of energy a system can have can change by doing work in the system.

The total energy of a system equals a constant.

Energy can be lost to: Work done by friction and lost to heat.

KE + PE at one place = KE + PE at another place

Power; Mechanical Power is how fast work is done or how fast

energy is generated or used up (dissipated).

Units: t’s

up. Power: Watts (W) or kiloWatts kW Work: J Time: s

Machines A machine is a device that

takes work (force x distance) and increases the applied force by decreasing the distance. It’s a trade off. You always need more input work than you get out because some work goes to overcome friction and heat.

There is no such thing as a 100% efficient machine.

You never get out more than you put in.

Simple machines Lever Pulley Screw Inclined

plane Wedge Wheel

and Axle

Which lever would require the least effort to lift the box ?

A C

B D

Levers load distance distance

force

fulcrum or pivotIf in balance: load x distance = distance x force

Efficiency: Machines A percentage of how much work you do

goes into doing the job.

Units: Efficiency is a %, no units Work: J

The 6 Simple Machines

Energy - Mass This is the connection

between mass and energy. Einstein’s equation.

Units: Energy: Joules (J) Mass: kg c = 3 x 108 m/s

Knows the effects of waves on everyday life.

Waves

Demonstrate wave interactions including interference, polarization, reflection, refraction, and resonance within various materials.

Wave A wave is a disturbance (energy) carried

through a material medium. (mechanical wave)

Light is an electromagnetic wave. It does not need a material medium to travel through.

There are two types of mechanical waves: Transverse waves are made perpendicular

to the medium. Longitudinal waves are made parallel to the

medium.

Wave Equation This is the equation you use with waves.

Units: Velocity: m/s Frequency: Hertz (Hz) Wavelength: m

Wave Parts

Frequency, f Frequency, f , is how many things

happen in one second. How many waves are made in 1 second. Frequency , f , is measured in Hertz, Hz.

Period, T The amount of time it takes to do

something once. The amount of time to make one wave. Period, T , is measured in seconds, s.

Wavelength, λ The length of one wave is called the

wavelength. It’s the distance from crest to crest,

trough to trough, or from corresponding part to like corresponding part.

Wavelength, λ , is .measured in meters, m

Amplitude The height of a wave from equilibrium,

or the depth of the wave from equilibrium.

Amplitude is usually measured in meters, m.

Medium The stuff that carries the wave.

Sound travels in air. Water waves travel in water. Earth quakes travel in dirt (earth) Light travels in empty space (light

is an electromagnetic wave and does not need a medium)

Wave Properties

Reflection When a wave hits a barrier it bounces off

at the same angle it hits the surface. When you look in the mirror you see

your reflection. The law of reflection is the angle of the

incoming ray equals the angle of the out going ray.

Refraction When a light ray changes mediums it

bends. The bending of alight ray is refraction.

When a wave changes mediums it refracts.

The change of direction of a ray of light, sound, heat, or the like in passing from one medium into another due to the change in the speed of the wave.

Diffraction The change in a wave as it passes by an

obstacle or through an opening. The spreading out of a wave as it passes

by a barrier.

Resonance Also called sympathetic vibrations. Something starts to vibrate or shake

because something else is vibrating.

Sound Sound is a longitudinal wave. It travels at around 340 m/s (constants

chart) The note or pitch of a sound wave is its

frequency. The loudness of the sound wave is its

amplitude. Sound needs a medium to travel through, this

medium is air. Sound are waves that our ears can pick up.

Light Light is a transverse wave. It is also an

electromagnetic wave. Light does not need a medium to travel

through. It travels at a maximum speed of 3 x 108

m/s, the speed of light (constants chart) This speed is also called c. White light has all the colors in the

rainbow. Roy G Biv.

Light The primary colors of

light are Red, Green, & Blue. RGB

Light colors are different frequencies (or wavelengths) of light.

Light we see is called the visible spectrum.

Light wavelengths are very small.

Electricity

Electric Circuits An electric circuit has three basic parts:

A source of electricity : a battery or outlet (voltage) Connectors that carry the electricity in a closed loop;

wires Objects that use electricity, resistors, light bulbs, etc.

The devices that use electricity and be connected: In series, one after the other. In parallel, there are multiple pathways (loops)

There must be a closed loop from one end (+ pole) of the battery to the other end (− pole)

Series Circuits When a circuit is connected in series;

The electrons coming out of the battery must pass through each device.

If the pathway is broken, all devices stop working.

The voltage is divided up with each device in the circuit.

The current (amps) is the same throughout the circuit.

Series Circuits

Parallel Circuits When a circuit is connected in parallel:

There are multiple pathways for electricity to travel.

Each device gets the same voltage, equal to the voltage of the battery.

The current coming out of the battery divides and takes separate paths to the other side of the battery.

If one device goes out, the rest can stay on. Most Christmas lights are connected in parallel. Houses are wired in parallel.

Parallel Circuits

Electrical Current (I) , Voltage (V), Resistance (R)

R’s up. Units

Current: Amperes (A) Voltage: Volts (V) Resistance: Ohms ()

Ohms Law Applied

Electrical Power How fast electricity is used (dissipated) or

made (generated)

Units: Power: Watts (W) Voltage: Volts (V) Current: Amperes (A)

Electrical Energy Energy due to electricity

Units: Energy: Joules (J) Power: Watts (W) Time: s

You must account for everything.The before equals the after.

Conservation Laws

Conservation of Mass The total mass before equals the total

mass after. Mass cannot be created or destroyed.

Conservation of Momentum The total momentum before equals the

total momentum after. In dealing with momentum, directions

matter.

Conservation of Energy The total energy before equals the total

energy after. Energy can change forms. Work is a form of energy.

Units: Length or distance (d):

meters m kilometers km centimeters cm millimeters mm

Density How much stuff is crammed into a volume.

How much mass is in a confined space.

Units: V’s up. Density: g/cm3 g/mL kg/m3 kg/L Mass: grams (g) kilograms (kg) Volume: liters (L) milliLiters (mL) cubic

meters (m3) cubic centimeters (cm3)

Heat Heat gained or lost. Heat is a form of energy.

Units: Heat: calories (cal) Calorie (Cal) kilocalorie

(kcal) Mass: grams (g) or kilograms (kg) Temperature: Celsius or centigrade (°C) Specific heat: should be given

Units: Time (t)

seconds s hours h minutes min

Mass (m) kilograms kg grams g

Units: Volume (V) Solid:

cubic meters m3

cubic centimeter cm3

Liquids: liters L ; l milliliters mL ; ml

Units: Force (F)

Newtons N

Work (W); Energy (E) , (KE) and (PE) Joules J

Power (P) Watts W kilowatts kW

Units: Frequency (f)

Hertz Hz

Electricity Voltage (V) Volts V Current (I) Amperes ; Amps

A Resistance (R) Ohms

Units: Density (D) mass per volume

kg/m3 g/cm3 kg/L g/mL

Velocity (v) speed distance per time m/s km/h cm/s

Acceleration (a) distance per time per time m/s/s m/s2 cm/s/s cm/s2

Units: Momentum (p) mass times velocity

kg m/s g m/s g cm/s

Work (W) Force times distance N m J

Power (P) Work per time N m/s J/s W

Units: Heat (Q)

calories cal Joules J

Acceleration due to gravity (g) 9.8 m/s2