An ice skater is spinning at 6.00 rev/s with his moment of inertia being 0.400 kg/m2. Calculate his new moment of inertia if he reduces his rate of spin to 1.25 rev/s by extending his arms and increasing his moment of inertia.

New moment of inertia will be

Explanation:

It is given initially angular velocity

Moment of inertia

Angular momentum is equal to

Now angular velocity is decreases to

As we know that angular momentum is conserved

So

So new moment of inertia will be

measuring things 1 litre of water

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me