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What does the top pressure gauge in the figure read?

physics help please???!!?

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Using Bernoulli's eqn.

P/ρg + v^2/2g + y = constant,

(P2 - P1)/ρg + [v2^2 - v1^2]/2g + (h2 - h1) = 0

=> (P2 - 200)/9.8ρ + [9 - 4]/19.6 + (3 - 2) = 0

=> P2 - 200 = - (1 + 5/19.6)*9.8ρ

=> P2 = 200 - 12.3ρ

To work out P, density ρ of the oil is needed without which answer cannot be worked out.

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The solution is as follows...

p for oil = 900 kg/m^3

P2 = P1 + 1/2*p*(Vi^2 - Vf^2) + p*g*(y1 - y2)

The gauges include 1 atm, but because you would add the value to the initial gauge and subtract it from the final gauge, it's arbitrary...

P1 = 200 kPa P2 = ?

V1 = 2.0 m/s V2 = 3.0 m/s

y1 = 0 m y2 = 10 m

1 atm = 101,300 Pa (Its really 101,325 but Mastering Physics is dumb)

You'll want to convert everything to Pa as your p of 900 will mess things up if you don't..

P2 = 200,000 + (1/2 * 900) * (2^2 - 3^2) + (900 * 9.8) * (0 - 10)

= 200,000 + (450) * ( -5 ) + (8,820) * (-10)

= 200,000 + -2250 + -88,200

= 200,000 - 90,450

P2 = 109550 Pa (Answer in 3 sig-figs)

P2 = 110 kPa

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