S8P3. Students will investigate relationship between force, mass, and the motion of objects. a. Determine the relationship between velocity and acceleration. b. Demonstrate the effect of balanced and unbalanced forces on an object in terms of gravity, inertia, and friction. c. Demonstrate the effect of simple machines (lever, inclined plane, pulley, wedge, screw, and wheel and axle) on work.

S8P5. Students will recognize characteristics of gravity, electricity, and magnetism as major kinds of forces acting in nature. a. Recognize that every object exerts gravitational force on every other object and that the force exerted depends on how much mass the objects have and how far apart they are.

Essential Questions 1.How are forces in nature related to the motion of objects? 2. How can forces be used to make objects move, change direction, or stop? 3.What are the similarities and differences between speed, velocity and acceleration? 4.What is friction and in what ways is it useful and in what ways is it problematic (e.g. in NASCAR races)? 5.How does gravity affect things on the earth? 6.How do simple machines make work easier for people?

Enduring Understanding Forces are the pushes or pulls in nature produced by interactions between objects. Forces can cause objects to start moving, stop moving, or change direction. Objects tend to keep on doing whatever they’re doing (Law of Inertia). An object at rest stays at rest and an object in motion stays in motion unless something else exerts a force on it. An object’s size (mass) and the amount of force exerted on it affect its speed and direction. When forces on an object are balanced, the object will either be at rest or move at a constant velocity. When forces on an object are unbalanced, the object will change its velocity. Acceleration occurs whenever there is a change in motion of an object. Acceleration can involve a change speed and/or direction and accelerations are caused by net forces. There are mathematical relationships between speed, velocity, acceleration, and time that can be used to help understand motion. Gravity refers to the force of attraction between any two objects in the universe that have a mass. The strength of this force of gravity depends on the mass of the objects and the distance between them. Since the earth is an object with a very large mass, things on or near the earth are pulled toward it by the earth's gravity. Energy is the ability to do work. Without energy, forces can’t be generated to make things move or change.

Vocabulary Acceleration Balanced forces Direction Distance Energy Friction Force Gravity Inertia Inclined Plane Law of Conservation of Energy Lever Mass Motion Position Pulley Screw Simple machines Speed Time Velocity Wedge Wheel and Axle Work

Resources: Velocity and Acceleration Balloon Cars Friction Gravity