A golf ball slides down a pipe from the upper level of a miniature golf course and heads directly for the hole on the green. Unfortunately, another
player's ball is directly in the way. The second ball, which is initially
at rest, moves forward with a speed of 3.0 m/s, causing it to land
in the cup. The first ball comes to a complete stop after the collision.
Both balls have a mass of 45 g. What is the first ball's speed before the
collision

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