In this deck, we'll explore the turning effect of forces, a concept known as moments. You'll learn how to calculate moments and apply this knowledge to understand how simple machines like levers and gears work. We will then move on to the concept of pressure, looking at how it's created and how it behaves in fluids like liquids and gases, including the air around us.

Imagine trying to loosen a tight nut with a spanner. If you push near the nut, it's very difficult. But if you push at the end of the spanner's handle, it's much easier. You're applying the same force, but you're creating a much larger turning effect. This turning effect of a force is called a moment. For any turning effect, there is always a fixed point that the object turns around. This point is called the pivot.

To calculate the size of a moment, you need to know two things: the size of the force you are applying, and the distance from the pivot to the point where you apply the force. The equation is: moment equals force multiplied by distance. It's crucial that the distance is the perpendicular distance from the pivot to the line of action of the force. This means the distance and the force must be at a right angle to each other. The standard unit for force is newtons, and for distance is metres, so the unit for a moment is newton-metres.