Chepter 4

1. Inertia

1.1. refer to the reluctance of a subject to change its state of rest or motion,due to its mass

1.1.1. Sub Idea 1

1.1.2. Sub Idea 2

1.2. The larger mass, the larger inertia

1.3. Examples: seat belt, shaking the droplets

1.4. No unit as it is not a physical quantity

1.5. found from Newton's First Low

2. Weight

2.1. Definition: the force acting on one subject due to gravity

2.2. SI unit: Newton ( N )

2.3. weight changes with the change of g : w=mg

3. Mass

3.1. Definition: the amount of matter in a body

3.1.1. Goal 1

3.1.2. Goal 2

3.2. SI unit: kilogram ( kg )

3.2.1. Session Rule 1

3.2.2. Session Rule 2

3.3. Do not change due to the gravitational field strength

4. Gravitational Field Strength ( g )

4.1. Definition: the gravitational force acting per unit mass

4.2. The gravitational field strength at a place equals to the acceleration of free fall at the same place ( g=a )

4.3. we always use g of earth =10N/kg ,g of the moon = 1.7N/kg

5. Density

5.1. ρ=mass (m) / volume (v)

5.2. SI unit : kilogram (kg) / cubic meter (m3)

5.3. The density of an object is its mass per unit volume