This table shows the weights of four different objects that are sitting on the floor
Weight (N)
25
Object
1
2
3
33
16
4
8
A person tries to lift each object with a force of 18 N, upward. Which
statement is supported by the data in the table?
A. All of the objects will move, and object 2 will accelerate upward
the fastest
B. None of the objects will move, but the normal force on all of the
objects will increase.
C. Objects 1 and 2 will not move, and objects 3 and 4 will accelerate
upward.
O D. Objects 1 and 2 will move downward, and objects 3 and 4 will
move upward

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