You're playing a game of pool (billiards). The cue ball hits the yellow stripe ball. The cue ball has a mass of 0.5 kg. Before the collision the cue ball was traveling at 2 m/s and the yellow stripe ball was holding still. After the collision the two balls stick together and move off together at 1 m/s. What is the mass of the yellow stripe ball?

it would be c. predictability

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