A STUDENT SHOULD KNOW THAT:

A. NEWTON'S LAWS OF MOTION.

1. First law (Law of Inertia) -- An object remains at rest or in uniform motion unless acted upon by an unbalanced force. The motion of an object will remain unchanged unless acted upon by an unbalanced force.
2. Second law (F=ma) -- An unbalanced force acting on an object causes an acceleration which is directly proportional to the force and in the direction of the force. The acceleration will vary directly with the magnitude of the force and inversely with the mass of the object.
3. Third law -- If one body exerts a force on a second body, then the second body exerts a force equal in magnitude and opposite in direction on the first body.

B. GRAVITATION IS A UNIVERSAL FORCE THAT EACH MASS EXERTS ON ANY OTHER MASS.

1. The strength of the gravitational attractive force between two masses is proportional to the masses and inversely proportional to the square of the distance between them.
2. Every object experiences this force of attraction, but, when the masses are relatively small, the forces are also small.

C. ELECTRIC FORCE IS A UNIVERSAL FORCE THAT EXISTS BETWEEN ANY TWO CHARGED OBJECTS.

1. Opposite charges attract; like charges repel.
   1. If two objects have an excess of electrons (and therefore have negative charges), they will repel each other.  However, if one object has an excess of electrons and the other object has a deficit, they will attract each other.
   2. Static electricity describes electrical charges at rest, i.e., no net transfer of charge in any given direction.  Static charges are most evident in dry environments.
2. The strength of the force that exists between any two charged objects is proportional to the charges and, as with gravitation, inversely proportional to the square of the distance between them.

D. MECHANICAL ENERGY IS EITHER KINETIC OR POTENTIAL.

1. Potential energy is energy that is stored.  Potential energy depends on the position or condition of the object.
2. Kinetic energy is the energy of an object due to its motion.  The faster an object moves, the more kinetic energy it has.

E. THE TOTAL AMOUNT OF ENERGY IS CONSTANT IN A CLOSED SYSTEM.  (CONSERVATION OF
    ENERGY) WITHIN A CLOSED SYSTEM, ENERGY CAN CHANGE FROM ONE FORM TO ANOTHER
    BUT THE TOTAL AMOUNT OF ENERGY ALWAYS REMAINS CONSTANT.

TO UNDERSTAND THE CONCEPTS OUTLINED ABOVE, A STUDENT SHOULD BE
ABLE TO:

• Determine relative force, mass or acceleration of a particular object given experimental data that illustrate the relationship between force, mass, and acceleration.
• Identify the change in the gravitational force of attraction when the masses and/or the distance is varied.
• Explain the similarities and differences between gravitational  forces and electrical forces that act at a distance.
• Describe the forces acting in an action-reaction pair.
• Determine, given data about a falling object, the relative kinetic and potential energy at any point in a closed system.