Unsteady drainage — time required to empty a hemispherical vessel through a bottom orifice (question text lacks complete parameters and is therefore incomplete).

Difficulty: Easy

• t = (2A / (a * sqrt(2 * g))) * (sqrt{2R} + R * ln((R + sqrt{2R})/R))
• t = (A / (a * g)) * (H + H^2)
• t = (2A / (a * sqrt(2 * g))) * (sqrt{H} + R * ln((R + sqrt{H})/sqrt{R}))
• None of these
• t = (A / a) * sqrt(2 * g * H)