the rotating blades of a hovering heicopter sweep out an area of radius 4m imparting a downward velocity of 12m/s to the air displaced. A) find the mass of the helicopter. B) the speed of rotation of the blades of the helicopter is increased so that the air now has a downward velocity of 13m/s. find the upward acceleration of the helicopter

This is a form of winter precipitation. it is frozen precipitation falling as ice pellets. snowflakes melt into raindrops as they pass through a thin layer of warmer air. the raindrops then refreeze into particles of ice when they fall into a layer of sub-freezing air near the surface of the earth. this precipitation is called a) hail. b) rain. c) sleet. d) snow.