# Chapter 4 (Physics.)

Get Started. It's Free Chapter 4 (Physics.) ## 2. Weight

### 2.2. SI UNIT

2.2.1. Newtons (N)

### 2.3. Measured in:

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

## 3. Inertia

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

3.1.1. Depends on mass : Greater mass , greater inertia

## 4. Mass

### 4.2. Units:

4.2.1. kilogram (kg) [SI unit]

4.2.2. grams (g)

4.2.3. tonnes

### 4.3. Instruments used to measure:

4.3.1. Beam balance

4.3.2. Sliding balance

## 5. Gravitational Field Strength

### 5.1. Gravitational force acting per unit mass on an object

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

### 5.3. Examples:

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

5.3.2. 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