An airplane pulls a 25-kg banner on a cable as depicted in Figure P4.67. When the airplane has a constant cruising velocity, the cable makes an angle θ = 20° with the horizontal. 

(a) What is the drag force exerted on the banner by the air?

(b) The weather changes abruptly and the pilot finds herself in a 20-minute rainstorm. After the storm, she finds that the cable now makes an angle θ_water = 30°. Assuming the velocity and drag force are the same after the storm, find the mass of the water absorbed by the banner’s fabric during the storm.

Figure P4.67

Reasoning and Relationships