▸The angular momentum is 5 kg·m²/s.
- Angular momentum is the rotational analog of linear momentum: it combines how mass is spread out (moment of inertia) with how fast the object spins (angular velocity).
- It is conserved when no external torque acts, which is why a spinning skater speeds up as they pull their arms in, lowering their moment of inertia.
- Reverse the spin direction and L changes sign; the magnitude shown here is what stays constant in a closed system.
- The same spin stores 25 J of rotational kinetic energy (½Iω²), which unlike L does depend on the square of the spin rate.
Next stepUse the moment of inertia calculator to find I for your shape, then feed it back here to get L.