How does air blowing over a u-tube affect the heights of water and oil columns?

In summary: This will cause the water level in the right arm to be hw-pb and the oil level in the left arm to be v-pa.
  • #1
JJMezzapesa
5
0
I really need help on this problem. I've been stuck forever

A U-TUBE AT BOTH ENDS IS PARTIALLY FILLED WITH WATER. OIL (DENSITY = 750KG/M2) IS THEN POURED INTO THE RIGHT ARM AND FORMS A COLUMN L=5.00 CM HIGH. DETERMINE THE DIFFERENCE h IN THE HEIGHTS OF THE TWO LIQIUD SURFACES. THE RIGHT ARM IS THEN SHIELDED FROM ANY AIR MOTION WHILE AIR IS BLOWN ACROSS THE TOP OF THE LEFT ARM UNTIL THE SURFACES OF THE TWO LIQUIDS ARE AT THE SAME HEIGHT. DETERMINE THE SPEED OF OF THE AIR BEING BLOWN ACROSS THE LEFT ARM. ASSUME THE DENSITY OF AIR IS 1.29 KG/M2
 
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  • #2
What work have you done?
 
  • #3
i don't know where to start
 
  • #5
The oil column will be higher than the water column since the density of the oil is less than that of water (1000 kg/m^3). The weight of the oil column can therefore be balanced by a smaller column of water. If one stays in the same liquid (water) then the pressure at the same level (or height) are equal. The pressure at pb is therefore the same at pc in the water. What you need to find is therefore the difference between 5 cm and hw. pa is the atmospheric pressure on top of the columns.
 
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  • #6
i was able to get the h without a problem but i am having trouble getting v
as I am not sure what i am comparing to solve for v
 
  • #7
The drawing will basically be the same with the top of the water level with the top of the oil in the other arm, that is the top of the liquids are on the same height in the two arms. The pressure on top of the water will be reduced to say [tex]p_r[/tex] by the air rushing over it.
 
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1. How does an U-tube work?

An U-tube is a simple apparatus used to demonstrate the principle of fluid equilibrium. It consists of a U-shaped glass tube partially filled with water or oil. When the tube is tilted, the liquid levels on either side of the tube will adjust until they are at the same height, showing that the pressure at the bottom of the two columns of liquid is equal.

2. Why does oil float on water in an U-tube?

This is due to the difference in density between oil and water. Oil is less dense than water, so it will float on top. In an U-tube, the oil will displace the water, causing it to rise up one side of the tube while the water remains at the same level on the other side.

3. Can you use any type of oil in an U-tube?

No, the type of oil used in an U-tube should have a lower density than water. Common oils used in U-tubes include vegetable oil, mineral oil, and baby oil. Using a denser oil, such as motor oil, will cause it to sink to the bottom of the U-tube instead of floating on top of the water.

4. What happens if you add food coloring to the water in an U-tube?

Adding food coloring to the water in an U-tube can help to make the demonstration more visible. As the colored water is displaced by the oil, it will create a more distinct separation between the two liquids, making it easier to see the equalization of pressure.

5. Can you use other liquids besides water and oil in an U-tube?

Yes, you can use other liquids with different densities in an U-tube to demonstrate the principle of fluid equilibrium. Some examples include honey and corn syrup, which have a higher density than water, or rubbing alcohol and vinegar, which have a lower density than water. However, oil is often used because it is less dense and easier to see the separation between the two liquids.

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