III. PHYSICS TOPICS

 
  1. Inquiry, Reflection, and Social Implications
  2. Motions of Objects
  3. Forces and Motion
  4. Forms of Energy and Energy Transformations

 

Additional Sites for Physics

 

P3. Forces and Motion

High School

    a. P3.1 Basic Forces in Nature
    Objects can interact with each other by “direct contact” (e.g., pushes or pulls, friction) or at a distance (e.g., gravity, electromagnetism, nuclear).

    1. Basic Forces in Nature New
      Site has good, easy-to-understand explanations of the different forces.
    2. Physics Animations
      Provides good application applets to help students visualize the motion of objects to help them better apply their knowledge.
    3. Four Fundamental Forces in Nature New
      Tutorial site that has basic, good graphics.
    4. Four Fundamental Forces of Nature New
      Tutorial of the four forces.
    5. Four Fundamental Interactions New
      Turtorial that also has chart with values for each fundamental force.
    6. Frank Potter's Science Gems
      Excellent site for student interaction with several concepts, including, force, motion, acceleration, gravity, velocity, etc... Includes several student activities where students are able to change the parameters. Contains many links to other sites on this subject.
    7. The Hindu: Understanding How the Basic Forces of Nature Work New
      Turtorial that may be more suited for teacher than students, but has a helpful model showing the four forces.
    8. TutorVista: Basic Forces in Nature New
      Tutorial with lists highlighting each force along with a couple equations.

    b. P3.2 Net Forces
    Forces have magnitude and direction. The net force on an object is the sum of all the forces acting on the object. Objects change their speed and/or direction only when a net force is applied. If the net force on an object is zero, there is no change in motion (Newton’s First Law).

    1. Applet: Net Force New
      Interactive site that allows user to change length of input vectors to see how reslutant vector changes.
    2. Calculating Net Forces - Examples New
      Printable worksheets with many problems solving for the net force, with answers.
    3. Net Force
      This site explains the nature of net force. It has drawings showing examples of net force acting on a textbook.
    4. Net Force - Animation
      This site allows the student to see how three forces act on an orange disk. Drag the heads of the arrows representing these forces to observe the effect on the net force.
    5. The Net Force
      The site explains why "Net Force" is important and how to find the net force. Tutorial site that has interactive quiz at the bottom of the page.
    6. The Physics Classroom: Force and Its Representation New
      Good tutorial site that has plenty of problems with available answers.
    7. The Physics Classroom - Net Force
      This site explains the calculations of net force acting upon an object. The site shows examples of calculations used to determine net force.
    8. Unbalanced Force = Net Force New
      Tutorial on net forces geared toward 8th graders.

    c. P3.3 Newton’s Third Law
    Whenever one object exerts a force on another object, a force equal in magnitude and opposite in direction is exerted back on the first object.

    1. LAW #3: Equal and Opposite
      Imagine a rocket is being launched from the earth. Hot gases are pushed out from the bottom of the rocket as the rocket is thrust upward. The force of the gases pushing against the surface of the earth is equal and opposite to the force with which the rocket moves upward.
    2. Lesson 4: Newton's Third Law
      A force is a push or a pull upon an object which results from its interaction with another object. Forces result from interactions!
    3. Newton's Third Law Applied to Aerodynamics
      For aircraft, the principal of action and reaction is very important. It helps to explain the generation of lift from an airfoil. In this problem, the air is deflected downward by the action of the airfoil, and in reaction the wing is pushed upward.
    4. Newton's Third Law of Motion: Astronauts in Outer Space New
      Outstanding - Video showing astronauts working in space and how Newton's third law applies. (~ 5 minutes long)
    5. Third Law of Motion New
      Tutorial site with a quiz at the end.

d. P3.4 Forces and Acceleration
The change of speed and/or direction (acceleration) of an object is proportional to the net force and inversely proportional to the mass of the object. The acceleration and net force are always in the same direction.

  1. Frank Potter's Science Gems
    Excellent site for student interaction with several concepts, including, force, motion, acceleration, gravity, velocity, etc... Includes several student activities where students are able to change the parameters. Contains many links to other sites on this subject.

e. P3.5x Momentum
A moving object has a quantity of motion (momentum) that depends on its velocity and mass. In interactions between objects, the total momentum of the objects does not change.

  1. Momentum
    The momentum of a particle is defined as the product of its mass times its velocity. It is a vector quantity. The momentum of a system is the vector sum of the momenta of the objects which make up the system.
  2. The Physics Classroom New
    This site contains a complete lesson on momentum and its conservation with many opportunites for the student to check their understanding.
  3. The Physics Department - Mechanics, Momentum
    Objects in motion are said to have a momentum. This momentum is a vector. It has a size and a direction. The size of the momentum is equal to the mass of the object multiplied by the size of the object's velocity. The direction of the momentum is the same as the direction of the object's velocity.
  4. Virtual Labratory Momentum Applet
    See the variables that affect momentum when a force is applied.

f. P3.6 Gravitational Interactions
Gravitation is a universal attractive force that a mass exerts on every other mass. The strength of the gravitational force between two masses is proportional to the masses and inversely proportional to the square of the distance between them.

  1. Microgravity Educator Guide New
    This educator guide contains excellent background information accompanied by classroom activities that enable students to experiment with the forces and processes that scientists who study microgravity are investigating today.
  2. Physics Classroom - "Circular Motion and Planetary Motion"
    Newton's laws of motion and kinematic principles are applied to describe and explain the motion of objects moving in circles; specific applications are made to roller coasters and athletics. Newton's Universal Law of Gravitation is then presented and utilized to explain the circular and elliptical motion of planets and satellites.
  3. Sir Isaac Newton: The Law of Universal Gravitation New
    This site offers general information on the Universal Law of Gravitation. It also discuss how gravity plays a role in orbits of planets and satellites.
  4. The Virtual Visitor Center - Gravitational Interactions
    The site explains the nature of gravitational interactions between two objects. This site explains several approaches to explain the nature of gravity: Quantum Gravity and the String Theory are explored.

    g. P3.7 Electric Charges
    Electric force exists between any two charged objects. Oppositely charged objects attract, while objects with like charge repel. The strength of the electric force between two charged objects is proportional to the magnitudes of the charges and inversely proportional to the square of the distance between them (Coulomb’s Law).

    1. Electric Charge and Coulomb's Law
      This site explains the nature of electric charge, the law of conservation of charge, electro static charging, and Coulomb's Law.
    2. Electrical Charge
      This is a School for Champions educational website.The site uses text and diagrams to explain the nature of electrical charges. The site has a mini quiz to check student's understanding.
    3. Electric Field Hockey New
      Play hockey with electric charges. Place charges on the ice, then hit start to try to get the puck in the goal. View the electric field. Trace the puck's motion. Make the game harder by placing walls in front of the goal.
    4. Physics4Kids - Coulomb Basics
      This site explains Coulomb's Law, one of the basic ideas of electricity in physics.

    h. P3.7x Electric Charges — Interactions
    Charged objects can attract electrically neutral objects by induction.

    1. Molecular Expression - Electricity and Magnetism
      Over 40 interactive Java tutorials can be found here that will support the study of physics. These include the effect of an electromagnetic field on a compass, cathode rays and Lenz's law.
    2. Physics 2000 - Electric Force Fields
      A basic explaination of electric force fields. Several Applets allow the user to explore how objects are affected by an electric field.
    3. Physics4Kids - Electric Field Basics
      The site explains electrostatic fields. The site explains how an electric field is created and how its strength can be measured. How capacitors store electrical charges is explained.
    4. The Physics Classroom - Charge and Charge Interactions
      Charge interactions and the influence of electric force on objects are explained at this site. The site also has a nice explaination of the methods of charging, and the nature of electircal force.

    I. P3.p8 Magnetic Force (prerequisite)
    Magnets exert forces on all objects made of ferromagnetic materials (e.g., iron, cobalt, and nickel) as well as other magnets. This force acts at a distance. Magnetic fields accompany magnets and are related to the strength and direction of the magnetic force. (prerequisite)

    1. Physics4Kids - Magnets
      This site explains how a magnet works and gives a good explaination of the different types of magnets.
    2. Physics4Kids - Magnetic Field Basics
      The site explains the difference between magnetic fields and electric fields. This site has everything you need to know about magnetic fields.

    j. P3.8x Electromagnetic Force
    Magnetic and electric forces are two aspects of a single electromagnetic force. Moving electric charges produce magnetic forces and moving magnets produce electric forces (e.g., electric current in a conductor.

    1. Build Beakman's Electric Motor
      See a very easy way for your middle or high school students to build and even take home a motor of their own for little money and easy to find materials.  Many links to similar sites and scroll down to the end for directions to build.  Note: Play with the motor yourself ahead of time, many materials can be adjusted from the suggested materials. (such as… ring magnets instead of rectangular, plastic cup for base instead of wood block, vary wire loop sizes by getting different dowel sizes instead of toilet paper roll, different gauge wire… many opportunities for discovery for students)
    2. Faraday's Electromagnetic Lab New
      Play with a bar magnet and coils to learn about Faraday's law. Move a bar magnet near one or two coils to make a light bulb glow. View the magnetic field lines. A meter shows the direction and magnitude of the current. View the magnetic field lines or use a meter to show the direction and magnitude of the current. You can also play with electromagnets, generators and transformers!
    3. How Stuff Works - Electric Motor
      A list of where electrical motors are used around the home and a diagram of an electric motor and it's parts and how they work. Continue on for two more pages about electric motors and their diagrams.

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