Mass, Weight and Density

1. Mass

1.1. SI unit is kg (kilograms)

1.1.1. Measured by beam balance

1.2. The amount of matter in an object

1.3. Is a scaler

2. Weight

2.1. Is affected by gravity

2.1.1. W=mg

2.2. The SI unit is N (Newton)

2.2.1. Measured by scale

2.3. Is a vector

3. Inertia

3.1. The reluctance for an object to change its state of rest or motion

3.2. affected by mass

3.2.1. The greater the mass the greater the inertia

3.3. Why we need seat belts in a car in case of a sudden break, due to inertia, the body will continue to move forward therefore needing the seat belt to exert the force needed to stop the body.

4. Gravitational field strength

4.1. The gravitational force acting per unit mass

4.2. Fnet=mg

4.3. The gravitational force of earth is 10N/kg