Closed cup
Suppose Shadlee has a closed cup so that air can't enter from the top. It has some fluid. The region above the fluid in the cup is a vacuum. 0.1 metres below the surface of the fluid, he poked a hole so that fluid starts spurting out. Suppose the surface of the water is A1 and the surface of the hole is A2= A1\1000 metres. What is the output velocity(in m/s) at this height? Submit your answer to one decimal place.
The answer is 1.4.
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1 solution
A2= A1/1000 metres, P1=0, h1=h, v1A1= v2A1/1000
According to Bernoulli's equation, we get
P1 + (row)pgh1 + (row)v1^2/2= P2 + (row)pgh2 + (row)pv2^2/2
2gX0.1 +(v2^2/1000000) = v2^2
Here the second term becomes negligible
v2 = (2X9.8X0.1)^0.5
v2 = 1.4metres