a figure skater rotating at 5.00 rad/s with arms extended has a moment of inertia of 2.25 kg·m2. if the arms are pulled in so the moment of inertia decreases to 1.80 kg·m2, what is the final angular speed?

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

305.7

explanation:

density =m/v

density =917/3.00

density = 305.

approximately = 305.7

in four significant figures