Electromagnetic radiation with a frequency of 8.6 x 1014 hz incident on an unknown metal surface causes ejection of photoelectrons with kinetic energies of 1.3 x 10–19 j. what is the unknown metal?

Panel bc in fig. p2.76 is semi-circular, with the 3 meter radius and horizontal straight edge through point b. compute (a) the hydrostatic force of the water on the panel, (b) its center of pressure, and (c) the moment of this force about point b. assume atmospheric pressure on the dry side of the panel