When a pin of mass 0.140 g is dropped from a height of 0.50 m, 0.05% of its energy is converted into a sound pulse by duration of 0.1 s. For both questions below, suppose that the intensity is I=P/4pir^2. (a) Estimate the range at which the dropped pin can be heard if the minimum audible intensity is 10-11 W/m2. (b) Your result in (a) is much too large in practice because of background noise. If you suppose that the intensity should be at least 10-8 W/m2 for the sound to be heard, estimate the range at which the dropped pin can be heard.