## Motion and Stability: Forces and Interactions

High School students who demonstrate an understanding of Forces and Interactions can:

#### PS2.A Forces and Motion

PS2.A.1
Newton’s second law accurately predicts changes in the motion of macroscopic objects.

Activity: Rocket Sledder

Activity: Friction

Activity: Skydiving

Activity: Push It!

Activity: Coffee Filter Physics

Activity: Carts, Bricks, and Bands

Activity: Weightlessness Training

PS2.A.2
Momentum is defined for a particular frame of reference; it is the mass times the velocity of the object. In any system, total momentum is always conserved.

Activity: Egg Drop

Activity: Inelastic Collisions

Activity: Elastic Collisions

Activity: Collisions

PS2.A.3
If a system interacts with objects outside itself, the total momentum of the system can change; however, any such change is balanced by changes in the momentum of objects outside the system.

#### PS2.B Types of Interactions

PS2.B.1
Newton’s law of universal gravitation and Coulomb’s law provide the mathematical models to describe and predict the effects of gravitational and electrostatic forces between distant objects.

Activity: Gravitational Fields

Activity: Coulomb's Law

PS2.B.2
Forces at a distance are explained by fields (gravitational, electric, and magnetic) permeating space that can transfer energy through space. Magnets or electric currents cause magnetic fields; electric charges or changing magnetic fields cause electric fields.

PS2.B.3
Attraction and repulsion between electric charges at the atomic scale explain the structure, properties, and transformations of matter, as well as the contact forces between material objects.

Activity: Name That Charge

Activity: Charge Interactions

Activity: Polarization