14. a test tube containing 4.00 g of iron and 2.40 g of sulfur was
heated in a manner similar to that of the copper-and-sulfur
experiment. before heating, the total mass of the tube and con-
tents measured on the balance was 36.50 g. after heating, the
mass was measured again. the mass of the tube and contents
was 36.48 g.

a. do you think it reasonable that mass remained the same was
conserved during this experiment?

b. what additional steps would you take to increase your confi-
dence in your answer to part (a)?

Alinearly polarized electromagnetic wave has an average intensity of 196 w/m^2. this wave is directed towards two ideal polarizers (in real polarizers, transmission is also effected by reflection and absorption). polarizer a is oriented with its transmission axis at an angle of θ_1=20.8∘ with the incident electric field. polarizer b has its axis at an angle of θ_2=63.0∘ with the incident electric field. what is the average intensity of the wave after it passes through polarizer a? what is the average intensity of the wave after it passes through polarizer b? suppose that the two polarizers a and b are interchanged. what would the average intensity be after passing through both polarizers?

If a stone with an original velocity of 0 is falling from a ledgeand takes 8 seconds to hoybthe ground whays the final velocity of the stone

This is the number of complete movements of a wave per second.