Theme 13 - Fluids 2

Question 1

What does the terms continuity mean (3)

Answer 1

• it says that whatever the volume of fluid in a pipe passing a particular point per second,
  -the same volume must pass every other point in a second
  -the fluid is not vanishing along the way

Question 2

State the equation of continuity (1)

Answer 2

P1v1a1 = p2v2a2

P = pressure at 2 different points the in the pipe
V = velocity of the fluid at points
A = area of the pipe

Question 3

State the equation of continuity of a liquid (incompressible fluid) (1)

Answer 3

A1v1 = a2v2
A = area of the pipe
V = velocity of the fluid at points

Question 4

What happens to the fluid when it moves from a wider area pipe to a narrower, state an equation (2)

Answer 4

It’s speed increases therefore work is done to it

W total = (pressure wider area - pressure smaller area) x change in volume

Question 5

State the equation of the kinetic energy of a fluid (2)

Answer 5

1/2(change in mass) x velocity^2

1/2(density x volume) x velocity^2

Question 6

State the equation which you get when you equate work done to KE (1)

Answer 6

P1 + 1/2 density x velocity^2 = P2 + 1/2 density x velocity^2

Question 7

The pipe has the same diameter but changes it’s height, what happens (1)

Answer 7

There’s work done on it against gravity

P1+ density x gravity x height1 = P2 + density x gravity x height 2

Question 8

State the Bernoulli’s equation

Answer 8

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