20. A ball of mass 6.0 kg, moving at 4m/s eastward, strikes head-on a ball of mass 20kg that is moving at 4m/s westward. The balls stick together after the impact. I Physics Semester 2 Final, 2020-2021 a What is the momentum of the first ball? b. What is the momentum of the second ball? c. What is the final velocity of the combined mass after the collision? d. What was the impulse for each ball? . ​

In an old-fashioned amusement park ride, passengers stand inside a 3.0-m-tall, 5.0-m-diameter hollow steel cylinder with their backs against the wall. the cylinder begins to rotate about a vertical axis. then the floor on which the passengers are standing suddenly drops away! if all goes well, the passengers will “stick” to the wall and not slide. clothing has a static coefficient of friction against steel in the range 0.60 to 1.0 and a kinetic coefficient in the range 0.40 to 0.70. part a what is the minimum rotational frequency, in rpm, for which the ride is safe? express your answer using two significant figures. f f = rpm