- #1

atay5510

- 10

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## Homework Statement

A valve for a pressure system has a discharge hole whose diameter is 50mm. The spring has a free length of 250mm (if you stretched the spring out), a coiled length (measured top to bottom while spring is coiled) of 207mm and a spring constant of 120kN/m. At what pressure will the valve open?

## Homework Equations

Not 100% but I think

a) p = F/A

b) F = kx

## The Attempt at a Solution

Area of discharge hole = ∏r

^{2}= 1.963x10

^{-3}m

^{2}

Force exerted by spring to keep hole closed = length of spring x spring constant = .207m x 120kN/m = 24.84kN

Therefore valve open pressure = 24.84kN/1.963x10

^{-3}m

^{2}= 12.65 kPa.

How does that look? There is a diagram with some other info attached but I'm not sure it's relevant.

Thanks!