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)

and 1and 1

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.