A 10-kg block slides down a smooth inclined surface as shown in Fig. P1.80. Determine the terminal velocity of the block if the \(0.1-\mathrm{mm}\) gap between the block and the surface contains SAE 30 oil at \(60^{\circ} \mathrm{F}\). Assume the velocity distribution in the gap is linear, and the area of the block in contact with the oil is \(0.1 \mathrm{~m}^{2}\).

Figure P1.80

0.1 mm gap 20