## Right-hand rule

‘Which way must I turn the bike wheel? Clockwise or counterclockwise?’ You can’t answer that because it depends on which side you look at it…

## Pulleys

With a rope over a pulley you lift a load of bricks. Naturally, you must lift the whole weight $w$ of the bricks. Their weight…

## Models

The finally fixed forest gravel path looks nice, smooth and flat. Perfect for a walk. You call your partner and say ‘the path is flat,…

## Falsification

How do we know that Newton’s 2nd law holds true? Honestly, we don’t. We can’t prove it. But we strongly believe it does. ‘How vague!’,…