23) a high school website directs parents to not allow student access to blue laser pointers or allow the students to bring them to school. it includes a video describing the danger inherent in the misuse of all laser pointers particularly the blue laser pointer. why would they claim that blue laser pointers are more of a concern than red laser pointers?

Consider a double atwood machine constructed as follows: a mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. the other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. using two suitable generalized coordinates, set up the lagrangian and use the lagrange equations to find the acceleration of the mass 4m when the system is released. explain why the top pulley rotates even though it carries equal weights on each side.