The intensity of a sound wave at a fixed distance from a speaker vibrating at a frequency f' is 11. (a) determine the intensity if the frequency is increased to f' while a constant displacement amplitude is maintained. (use it, f for f', and fas necessary.) 12 = (b) calculate the intensity if the frequency is reduced to f/7 and the displacement amplitude is tripled. 12 = x 11

The vector a? is 3.50 cm long and is directed into this page. vector b? points from the lower-right corner of this page to the upper-left corner of this page and has the components bx=-19.5 cm , by=25 cm. in the right-handed coordinate system, where the +x-axis directed to the right, the +y-axis toward the top of the page, and +z-axis out of the page, find the x-component of the vector product a? ×b? , measured in cm2.