Forces Introduction Forces can be classified as a push or pull acting on an object. Everything from opening a drawer to the Earth's gravitational pull is known as a force. Can you think of other examples? Forces have the capacity to change either the state of motion or the state of mass in the object which it applies to. You can also classify forces into two types: contact and non-contact force. However, it depends on if the forces are caused by contact or without it. They are known as contact and non-contact forces, respectively. To understand more clearly, you can refer to this example: A coin is falling from a building. Here, you will find two examples of forces. Can you find out what they are? The first force is the gravitational force, which does not touch the coin, yet it still applies a force onto it in a downwards motion. The second is the frictional force: in this case, it does have contact with the coin: air resistance is formed due to friction, meaning the air mol...