Farm Machinery

The radius of spherical curvature $R$ of a standard concave plow disc of diameter $D$ and disc depth $d$ is given by:

Options:

• (A) $R = \frac{D^2}{8d} + \frac{d}{2}$
• (B) $R = \frac{D}{2d}$
• (C) $R = \sqrt{D \cdot d}$
• (D) $R = \frac{D^2}{4d}$