# Chapter F1

Get Started. It's Free
Chapter F1

## 4. Types of Forces

### 4.1. Frictional Force

4.1.1. Friction is the force that opposes motion between 2 surfaces that are in contact

### 4.2. Gravitational Force

4.2.1. Gravity is the force of attraction that exists between objects that have mass.

4.2.2. The strength of the pull of gravity between 2 objects depends on their mass and the distance between them.

### 4.3. Magnetic Force

4.3.1. Magnetic force is the force of attraction and repulsion exerted by a magnet

## 6. How to Increase Pressure?

### 6.2. Example

6.2.1. A sharp knife has a small contact area with the object that needs to be cut. This ensures that the pressure is higher, making it easier for the knife to slice through and cut the things.

## 7. How to Decrease Pressure?

### 7.2. Example

7.2.1. Skis are long so that there is a larger area. With a larger area there is less pressure acting on it, so the chances of someone sinking into the snow while skiing is very low.