Before you read this, I suggest you read post 17.15. We will think about this question by considering a plane whose wings have the cross-sectional shape shown in the picture below. In this picture, the engines of the plane move it in the direction shown by the arrow. Now let’s think about the movement of… Continue reading 17.16 Why do planes fly?

Before you read this post, I suggest you read post 17.5. A fluid is anything that flows – like a liquid or a gas (post 16.37). In post 17.5, we saw that a fluid remains stationary when there is a surrounding pressure that acts equally in all directions. However, when the pressure is greater in… Continue reading 17.15 Fluid flow

According to the Bible (in the book of Genesis, chapters 9-11), the world was once covered by water, in a great flood. A man called Noah built a big ship (called the “ark”) that he used to rescue his family and all the species of animals. After the flood, his descendants lived in a place… Continue reading 17.14 Confusion

Before you read this, I suggest you read posts 17.12, 17.11, 17.10 and 17.4. The man in the picture is practising “throwing the hammer”. In this event, the participant swings a spherical “hammer” using a cable, as shown in the picture, several times around his/her body. So the hammer goes round in a circle, with… Continue reading 17.13 Centripetal force – throwing the hammer