Chapter 4 (Physics.)

1. A spring scale or hydraulic or pneumatic scale measures weight force (strictly apparent weight force) directly.

2. It is a body's reluctance to change its shape when it is moving.

3. Depends on mass : Greater mass , greater inertia

4. A greater inertia means that the body is more difficult to move and it is harder to change its shape.

5. Gravitational Field Strength (N/kg) = Acceleration due to gravity (m/s2)

6. Weight

6.1. A body's relative mass or the quantity of matter contained by it, giving rise to a downward force; the heaviness of a person or thing.

6.2. SI UNIT

6.2.1. Newtons (N)

6.3. Measured in:

7. Inertia

8. Mass

8.1. Mass is the amount of matter in an object.

8.2. Units:

8.2.1. kilogram (kg) [SI unit]

8.2.2. grams (g)

8.2.3. tonnes

8.3. Instruments used to measure:

8.3.1. Beam balance

8.3.2. Sliding balance

9. Gravitational Field Strength

9.1. Gravitational force acting per unit mass on an object

9.1.1. Therefore, it is dependent on the mass of an object

9.2. SI unit: N/kg

9.3. Examples:

9.3.1. The Moon experiences gravitational pull to the Earth, as Earth has a heavier mass and therefore a greater gravitational field strength

9.3.2. Although Mars has a smaller mass compared to Earth, it is not pulled towards the Earth but instead the Sun as the Sun has a greater mass and therefore greater gravitational field strength than the Earth so Mars is pulled towards the Sun