Question

A student needs to measure the drag on a prototype of characteristic length dp moving at velocity Up in air at sea-level conditions. He constructs a model of characteristic length dm, such that the ratio dp/dm = a factor f. He then measures the model drag under dynamically similar conditions, in sea-level air. The student claims that the drag force on the prototype will be identical to that of the model. Is this claim correct? Explain.

Answer 1

Answer: Yes

Explanation:

Since both the prototype of characteristics length dp and the model of characteristics length dm are moving at a velocity up in air and are both at sea level conditions, they tend to be pulled by the same drag force which acts downwards against their motion i.e product of mass and acceleration due to gravity.