Before you read this, I suggest you read posts 17.4 and 17.11. In the picture above, the point P is moving in a circular path around the point O. In a time-interval, Δt, it moves from P to P’, and sweeps out an angle Δθ. (In this post the symbol Δ, the Greek letter capital… Continue reading 17.12 Going round in circles

Before you read this, it might be useful to read post 16.7. The most common way to measure angles is to divide a complete revolution (for example, of a wheel) into 360 degrees, usually written as 360o. Then a right-angle is a quarter of a revolution, 360o/4 = 90o. Another way is to divide a… Continue reading 17.11 Measuring angles

Before you read this, I suggest you read post 16.50. Let’s suppose we want to use the (grey) spanner to loosen the (red) nut, in the picture above. We apply a force, F, that makes an angle θ with the axis of the spanner at a distance L from the axis around which the nut… Continue reading 17.10 Torque – using a spanner

Have you ever read the phrase, “Scientists believe that…”, or has anyone ever said it to you? What does it mean? I think it means that something is supposed to be too difficult for you to understand but somebody in authority believes it – so you ought to believe it too! Fortunately, science doesn’t work… Continue reading 17.9 Scientists believe that…