A 1 kg billiard ball collides head on with a 0.1 kg marble that sits at rest on the table. The marble moves at 3 m/s in the same direction the billiard ball was originally moving. The billiard ball continues after the collision at 0.3 m/s. What was the initial speed of the billiard ball?

Atrain is traveling at 30.0 m/s relative to the ground in still air. the frequency of the note emitted by the train whistle is 262 hz. the speed of sound in air should be taken as 344 m/s. what frequency (f approach) is heard by a passenger on a train moving at a speed of 18.0 m/s relative to the ground in a direction opposite to the first train and approaching it? what frequency (f recede) is heard by a passenger on a train moving at a speed of 18.0 m/s relative to the ground in a direction opposite to the first train and receding from it?