Question

It has been found that $9$ feet below the surface of water , the pressure is $18.7$ pounds per square inch . The sea level pressure at a depth of $14$ feet is $20.9$ pounds per square inch. If the pressure increases linearly as one descends further , find the model that best fit in with pressure $p$ in pounds per square inch at depth of $d$ feet below the surface?

• A. $p=0.44d+0.77$
• B. $p=0.44d+14.74$
• C. $p=2.2d-1.1$
• D. $p=2.2d-9.9$

Answer 1

The correct option is B $p=0.44d+14.74$

Consider depth as y-axis and pressure along.

Given, At $9$ feet below,pressure is $18.7$ pounds per inch.

At $14$ feet below,pressure is $20.9$ pounds per inch.

Slope$=\frac{20.9-18.7}{14-9}=0.44$

So,pressure as a function of depth is,

$(p-18.7)=0.44(d-9)$

$p=0.44d+14.74$