Question

Drag force $F$ depends on density $\rho$, velocity $V$, and diameter $D$: $F = k \rho^a V^b D^c$. Find exponents $a, b, c$.

• A. $(1, 2, 1)$
• B. $(2, 2, 1)$
• C. $(1, 1, 2)$
• D. $(1, 2, 2)$

Hint:

The standard drag force formula is:
$F_d = \frac{1}{2} C_d \rho A V^2$
Since area $A \propto D^2$, the force is proportional to $\rho^1 V^2 D^2$. This matches $(1, 2, 2)$ perfectly.

Answer 1

The Correct Option is D