posted by Urvashi .
When a paper cake case falls right way up through air, it quickly reaches terminal velocity. The drag force, D acting on the case is given by D=f§¤Av©÷ where §¤ is the density of air (1.2kg/m©ø), v is the terminal velocity, A is the cross-sectional area of the base of the case, f is known as he shape factor. Can you plz help me to devise an experiment to determine the shape factor for empty cases?
You will have to know the velocity of the box in the airstream. Two ways: drop it from a height, and measure the fall of the box with a video camera, then determining its velocity. You can measure the crossectional area. Let it hit a scale, and record f.
another way: Use a auto to generate motion attach a box to a string which is attached to spring scale. At a constant veloctity, let the box into the airstream behind the car. Measure the force on the spring.