When a stone is thrown into the air it's surface will be in contact with the surrounding air. Analyse the stresses existing between the stone and the surrounding air.
1 answer
The collisions of the stone with air molecules tend to slow the stone down slightly. A frictional force called drag is exerted upon the stone. It is of two types: (1) pressure drag (higher pressure in front that behind) and (2) boundary layer friction along the sides.