A traveling electromagnetic wave in a vacuum has an electric field amplitude of 74.5 V/m. Calculate the intensity S of this wave. Then, determine the amount of energy U that flows through area of 0.0285 m 2 over an interval of 13.3 s, assuming that the area is perpendicular to the direction of wave propagation.

Acarpenter is driving a 15.0-g steel nail into a board. his 1.00-kg hammer is moving at 8.50 m/s when it strikes the nail. half of the kinetic energy of the hammer is transformed into heat in the nail and does not flow out of the nail. what is the increase in temperature of the nail after the three blows that the carpenter needs to drive the nail in completely? the specific heat of steel is 448 j/kg ∙ k. a) 2.7 k b) 1.8 k c) 7.7 k d) 8.1 k e) 3.6 k