# 17.20 Falling

Before you read this, I suggest you read post 17.19. This post illustrates the application of integration to calculate velocity and speed from acceleration, as described in post 17.19. In this post, we will consider an object (like the rock in the picture above) falling close to the surface of the earth, so that the… Continue reading 17.20 Falling

# 17.19 Calculating distances from speeds – integration

Before you read this post, I suggest you read post 17.4. This post introduces the mathematical concept of integration that makes it much easier to understand many scientific topics. But, if you really don’t like mathematics, you can ignore this post and still understand most parts of most other posts. To keep it simple, I’m… Continue reading 17.19 Calculating distances from speeds – integration

# 17.18 Terminal velocity and parachutes

Before you read this, I suggest you read post 17.17. If we ignore viscosity (post 17.17), an object of mass m that falls from a height h, gains a speed of v =√(2gh) (post 16.42), where g is the magnitude of the earth’s gravitational field (post 16.16). This result was derived by assuming all the… Continue reading 17.18 Terminal velocity and parachutes

# 17.17 Drag and viscosity

Try pushing your finger slowly through a glass of water: now try to do the same in a glass of treacle or honey. You will find that the treacle or honey exerts a force (post 16.13), resisting the motion of your finger (rather like friction in post 16.19), that is much greater than the force… Continue reading 17.17 Drag and viscosity