Two shuffleboard disks of equal mass, one orange and the other yellow, are involved in an elastic, glancing collision. the yellow disk is initially at rest and is struck by the orange disk moving with a speed of 5.60 m/s. after the collision, the orange disk moves along a direction that makes an angle of 35.0° with its initial direction of motion. the velocities of the two disks are perpendicular after the collision. determine the final speed of each disk.

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