Usable chemical energy in food begins as energy. a) heat b) sound c) light d) mechanical motion

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

The star nearest to our sun is proxima centauri, at a distance of 4.3 light-years from the sun. how far away, in km, is proxima centauri from the sun?

What energy transformations occur each time the skateboarder rolls up the ramp?