• For any pair of interacting objects, the force exerted by the first object on the second object is equal in strength to the force that the second object exerts on the first, but in the opposite direction (Newton's third law). (6-8)
• The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. The greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion. (6-8)
• Momentum is defined for a particular frame of reference; it is the mass times the velocity of the object. (9-12)

• The gravitational force of Earth acting on an object near Earth's surface pulls that object toward the planet's center. (5)

• Motion energy is properly called kinetic energy; it is proportional to the mass of the moving object and grows with the square of its speed. (6-8)

• When the motion energy of an object changes, there is inevitably some other change in energy at the same time. (6-8)
• Energy cannot be created or destroyed, but it can be transported from one place to another and transferred between systems. (9-12)
• Mathematical expressions, which quantify how the stored energy in a system depends on its configuration (e.g. relative positions of charged particles, compression of a spring) and how kinetic energy depends on mass and speed, allow the concept of conservation of energy to be used to predict and describe system behavior. (9-12)

• When two objects interact, each one exerts a force on the other that can cause energy to be transferred to or from the object. (6-8)

• Energy cannot be created or destroyed—it only moves between one place and another place, between objects and/or fields, or between systems. (9-12)

• 9-12: 2B/H3. Mathematics provides a precise language to describe objects and events and the relationships among them. In addition, mathematics provides tools for solving problems, analyzing data, and making logical arguments.

• 6-8: 4E/M2. Energy can be transferred from one system to another (or from a system to its environment) in different ways: 1) thermally, when a warmer object is in contact with a cooler one; 2) mechanically, when two objects push or pull on each other over a distance; 3) electrically, when an electrical source such as a battery or generator is connected in a complete circuit to an electrical device; or 4) by electromagnetic waves.
• 6-8: 4E/M4. Energy appears in different forms and can be transformed within a system. Motion energy is associated with the speed of an object. Thermal energy is associated with the temperature of an object. Gravitational energy is associated with the height of an object above a reference point. Elastic energy is associated with the stretching or compressing of an elastic object. Chemical energy is associated with the composition of a substance. Electrical energy is associated with an electric current in a circuit. Light energy is associated with the frequency of electromagnetic waves.

• 6-8: 4F/M3a. An unbalanced force acting on an object changes its speed or direction of motion, or both.
• 9-12: 4F/H1. The change in motion (direction or speed) of an object is proportional to the applied force and inversely proportional to the mass.
• 9-12: 4F/H7. In most familiar situations, frictional forces complicate the description of motion, although the basic principles still apply.
• 9-12: 4F/H8. Any object maintains a constant speed and direction of motion unless an unbalanced outside force acts on it.

This collection of short videos explores the basic physics of football in a way that's sure to spark interest among kids. Each video features an NFL player, file footage of games, slow-motion video captured with a super high-speed Phantom Cam. Physicists appear in each video to explain the concepts and clarify the connection to physics. Topics: Newton's Laws, momentum, inertia, vectors, center of mass, projectile motion, and more.

• Physical Sciences K-8 Special Collections Unit
• Physics First Special Collections Unit
• Conceptual Physics Special Collections Unit
• Algebra-Based Physics Special Collections Unit
• AP/Calculus-Based Physics Special Collections Unit