For the system shown below, what is the critical angle (angle at which the system just begins to move)? assume that the coefficient of friction between all flat surfaces is 0.0500 and that the pulley is frictionless. the mass of m1 is 76.00 kg and the mass of m2 is 194.00 kg. express your answer in radians.

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?