the forming section of a plastics plant puts out a continuous sheet of plastic that is 1.2 m wide and 2 mm thick at a rate of 18 m/min. the sheet is subjected to airflow at a velocity of 4 m/s on both top and bottom surfaces normal to the direction of motion of the sheet. the width of the air cooling section is such that a fixed point on the plastic sheet passes through that section in 2 s. using properties of air at 1 atm and 60 o c, determine the drag force the air exerts on the plastic sheet in the direction of airflow