# 17.12 Going round in circles

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

# 17.11 Measuring angles

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

# 17.10 Torque – using a spanner

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

# 17.9 Scientists believe that…

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…