A meteorologist is studying hurricanes and tornadoes. She determines that a particular historic tornado can be described by phi7. At a distance 1 km from the eye of the tornado (the eye is at the origin of the coordinate system) the radial velocity is 1 km/hr (inward towards the origin) and the tangential velocity is 1 km/hr. The pressure 1 km from the eye of the tornado is 14.7 psia. A neutrally buoyant balloon is released 1 km from the center of the tornado. How long will it take to move to a point that is 50 m from the center?