A new aircraft wing design is being tested using a $1$:$20$ scale model in a wind

tunnel. The full$-$size aircraft flies at $250\frac{m}{s}.$ Determine the velocity at which the

model should be tested to ensure dynamic similarity, using the Reynolds number

for scaling. Assume the air properties are the same in both cases, and that the

characteristic length for scaling is the chord length of the wing $(L=2\mathrm{.}5m$ for the

real aircraft$).$