The speed of a bobsled is increasing because it has an acceleration of 2.0 m/s2. at a given instant in time, the forces resisting the motion, including kinetic friction and air resistance, total 450 n. the mass of the bobsled and its riders is 255 kg. (a) what is the magnitude of the force propelling the bobsled forward

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