## Nutation

You might see a gyroscope “wobble” while precessing. It might look like the precession is unstable and “nods” up and down. Such “nodding” – let’s…

## Spinning & precession

Why does a spinning toy top not fall over? How can a plate balance on a stick only when spinning fast? And why doesn’t the…

## Newton’s 3rd law vs 2nd law

Newton’s 2nd law told us that unbalanced forces cause acceleration. But Newton’s 3rd law now tells that forces always come in pairs, equal but opposite…

## Reaction forces

Take a step. You exert a stepping force on the ground. It is of course at an angle. The horizontal part $F_{\text{step}\parallel}$ pushes along the…

## Elastic & inelastic collisions

‘Jumping on a trampoline’ and ‘jumping on asphalt’ are of course two very different feelings. The “impact” with the surface is very different. In one…

## Rotational stability & gyroscope

The phenomenon of precession explains why a spinning top keeps spinning, and even why a tilted spinning top keeps that same tilt (while rotating –…

## Angular momentum conservation

Just like we have a linear momentum conservation law telling us how the sum of all momentum never changes (the same before and after any…