Pleas help Above On a disk is an iron cube of mass 200g, at a distance of 10cm from the axis of rotation of the disk, fig.3.95. The coefficient of friction of the rest of the cube with the disk is 0.4. Find: a) How many revolutions per minute does the disk make the moment the iron cube slides from the disk. b) The centripetal force acting on the cube before the moment of sliding from the disk.

An alpha particle with kinetic energy 12.5 mev makes a collision with lead nucleus, but it is not "aimed" at the center of the lead nucleus, and has an initial nonzero angular momentum (with respect to the stationary lead nucleus) of magnitude l = p0 b, where p0 is the magnitude of the initial momentum of the alpha particle and b=1.40×10−12 m. (assume that the lead nucleus remains stationary and that it may be treated as a point charge. the atomic number of lead is 82. the alpha particle is a helium nucleus, with atomic number 2.) what is the distance of closest approach?