Need help with horizontal syringe Bernoulli's Principle problem.

Thread starter b0b10
Start date Aug 30, 2019
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Bernoulli's Bernoulli's principle Horizontal Principle Syringe

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The discussion revolves around a problem involving Bernoulli's Principle and a horizontal syringe. The original poster doubts their solution, expecting an answer around 50 m/s. Other participants confirm that the calculations appear correct. The consensus suggests that the initial work aligns with the expected outcome. Clarification on the application of Bernoulli's Principle in this context is emphasized.

Aug 30, 2019

b0b10

Homework Statement: Dr. Jane is ready to inject medicine into Bob. The hypodermic syringe she uses contains a medicine with the same density as water. The barrel of the syringe has a cross-sectional area of 2.50 x 10^-5 m^2. The cross-sectional area of the needle is 1.0 x 10^-8 m^2. In the absence of a force on the plunger, the pressure everywhere is atmospheric pressure. A 2.0 N force is exerted on the plunger, making medicine squirt from the needle to insure there is no air in the needle prior to giving the shot. Determine the speed of the emerging fluid. Assume that the pressure in the needle remains at atmospheric pressure, that the syringe is horizontal, and the speed of the emerging fluid is the same as the speed of the fluid in the needle.

Relevant Equations: (P1) + ρg(y1) + 0.5ρ(v1)^2 = (P2) + ρg(y2) + 0.5ρ(v2)^2
P=F/A
(A1)(v1) = (A2)(v2)

Did I do this problem correctly? I felt like I did this wrong because the answer is suppose to be around 50 m/s.

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Aug 30, 2019

TSny

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Your work and answer look correct to me.

Aug 31, 2019

b0b10

TSny said:

Your work and answer look correct to me.

Thx

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