Draw magnetic field (b field) line diagrams for the following. make sure the diagrams are large enough so the direction and shape of the magnetic field is very clear. include magnetic field lines that are far from their sources. a. a bar magnet (be sure to label the north and south pole). b. a horseshoe magnet (be sure to label the north and south pole). c. a long straight wire with an electric current in it (be sure to label the direction of the current).

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