Aceiling fan consists of five blades of 0.80 m length and 0.10 m width, which rotate at 100 rpm. estimate the torque needed to overcome the friction on the blades if they act as flat plates. (hint: at each location r along the length of the plate, the approach velocity will be 2πn×y where 0 < y < l and l is the blade length (0.8 m) and n is the rotational speed (rpm).