5) A lighthouse is located on a small island 4 km away from the nearest pointPon a straight shoreline and its light makes four revolutions per minute. How fast is the beam of light moving along the shoreline when it is 1 km fromP?

6) When air expands adiabatically (without gaining or losing heat), its pressurePand volumeVare related by the equationPV1.4 =C, whereCis a constant. Suppose that at a certain instant the volume is 750 cm^3 and the pressure is 80 kPa and is decreasing at a rate of 10 kPa/min. At what rate is the volume increasing at this instant?