The energy required to dislodge electrons from cesium metal via the photoelectric effect is 207 kj/mol . what wavelength (in nm) of light has sufficient energy per photon to dislodge an electron from the surface of cesium?

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.