What is the binding energy of an electron that requires a photon with a maximum wavelength of 430 nm to eject it? If a photon with a frequency of 8.21 x 1015 Hz is used, what is the kinetic energy of the electron?

During a medieval siege of a castle, the attacking army uses a trebuchet to hurl heavy stones at the castle walls. if the trebuchet launches the stones with a velocity of at an angle of 50.0°, (a) how long does it take the stone to hit the ground? (b) what is the maximum distance that the trebuchet can be from the castle wall to be in range? (c) how high will the stones go? show all your work.