A disk-shaped merry-go-round of radius 1.87 m and mass 123 kg rotates freely with an angular speed of 0.821 rev/s. A 62.5-kg person running tangential to the rim of the merry-go-round at 2.28 m/s jumps onto its rim and holds on. Before jumping on the merry-go-round, the person was moving in the same direction as the merry-go-round's rim. What is the final angular speed of the merry-go-round?

at positions a, g kinetic energy is maximum.

at position d, potential energy is maximum.

does anyone know or what?

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

the answer is 12 as i may remember

: )