The earth is compressed to the size of the moon. Calculate the acceleration due to gravity of the newly formed earth based on the data given below. Mass of the earth = 6 x 1024 kg Mass of the moon = 7.2 x 10-2 kg Radius of the earth = 63800 km Radius of the moon = 1.7 x 103 km (g = 138.47 m/s)

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