SOLUTION: Rational Expressions and Equations A marine biology submarine was searching the water for blue whales at 50 feet below the surface where it experienced a pressure of 21 pounds

Question 271780: Rational Expressions and Equations

A marine biology submarine was searching the water for blue whales at 50 feet below the surface where it experienced a pressure of 21 pounds per square inch. The pressure of an object varies directly with its distance beneath the surface
question A. Write the relationship between the pressure and depth, using p to represent pressure, d to represent the depth and k to represent the constant of variation.
Answer by Theo(13342) (Show Source): You can put this solution on YOUR website!
the formula for direct variation is y = k*x

let y = the pressure.
let x = the depth.

you get:

21 = k*50

this makes k = 21/50 = .42

your constant of variation is .42

at 0 depth, the pressure should be 0.

based on this formula, the pressure at 0 feet is equal to:

y = 0*.42 = 0

this would be additional pressure over the normal pressure of the atmosphere.

at 10 feet, the pressure would be:

y = 10*.42 = 4.2 pounds per square inch.

at 50 feet, the pressure would be:

y = 50 * .42 = 21 pounds per square inch.

at 100 feet, the pressure would be:

y = 100 * .42 = 42 pounds per square inch.

you can see that as x gets greater, y gets greater which means they are directly proportional.

here's some additional information on variation for you.

http://www.purplemath.com/modules/variatn.htm

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