Lecture 03 - Bernouilli's principle

Lecture 03- - 1 Lecture 3 Bernouilli’s equation Bernouilli s equation ACT Aluminum and lead Two blocks of aluminum and lead with identical sizes

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 Lecture 3 Bernouilli’s equation Bernouilli s equation. ACT: Aluminum and lead Two blocks of aluminum and lead with identical sizes are suspended from the ceiling with strings of different lengths and placed inside a bucket of water as shown. In which case is the buoyant force greater? A. Al B. Pb ceiling C. It’s the same for both Al The displaced volume (= volume of the block) is the same in both cases. Depth or object density do not play any role. Pb The different weight is compensated with a different tension in the strings. Work by pressure A As an element of fluid moves during a short interval dt , the ends move distances ds 1 and ds 2 . 1 1 2 2 dV Ads Ads = = dV dV If the fluid is incompressible, the volume should remain constant: A 1 A 2 v 1 v 2 ( ) 1 1 1 2 2 2 1 2 dW pAds p Ads p p dV = − = − Work by pressure during its motion: ρ 1 ρ 2 ds 2 ds 1 Kinetic and gravitational potential energy ( ) ( ) 2 2 2 1 1 1 2 2 dK dV v dV v ρ ρ = − Change in kinetic energy: Change in potential energy: ( ) 2 1 dU g dV y y ρ = − y: height of each element relative to some initial level (eg: floor) A 1 A 2 v 1 v 2 ρ 1 ρ 2 ds 2 ds 1 2 Bernouilli’s equation Putting everything together: ( ) ( ) ( ) ( ) 2 2 2 1 2 1 1 2 1 1 2 2 dV v dV v g dV y y p p dV ρ ρ ρ − + − = − ( ) other d K U dW + = 2 2 1 1 1 2 2 2 1 1 2 2 p v g y p v...
View Full Document

This note was uploaded on 09/21/2011 for the course PHYS 222 taught by Professor Johnson during the Spring '07 term at Iowa State.

Page1 / 5

Lecture 03- - 1 Lecture 3 Bernouilli’s equation Bernouilli s equation ACT Aluminum and lead Two blocks of aluminum and lead with identical sizes

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online