A wheel is used to turn a valve stem on a water valve. The wheel radius is 4 inches and the axle radius is .25 inches.

a)What is the mechanical advantage of the wheel and axle?

b)How much resistance force can be overcome when an effort of 6 lbs is applied to the wheel of the water valve in this problem?

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