How do you calculate the work function of a metal without being given the frequency for the photoelectric effect? i am only given the speed the electrons are ejected from the metal, and the energy from the light that struck the electrons. i have used E = hf to find the frequency but I don’t know how to find the kinetic energy to plug into the photoelectric equation KE = hf - (work function)

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.