Question

A large tank is filled with pressurized air. If a valve is opened and air is allowed to escape, where will the streamlines of the flow end in the tank? O (A) The streamlines will end on the walls of the tank. O (B) The streamlines will end in the volumetric center of the tank. 0 (C) The streamlines will end in the fluid in the tank where the fluid velocity is approximately zero. (D) The ending point for the streamlines cannot be determined without knowing where the orifice is located. Which of the following statements concerning surface tension is FALSE? (A) Surface tension increases with increasing temperature. (B) Surface tension depends on the gas in contact with the liquid. (C) Surface tension influences the boiling point of a liquid. (D) The force caused by surface tension is constant as a film is stretched.

Answer 1

Question 1 : (A) The Streamlines will end on the walls of the tank.

The reason is, since the tank is filled with pressurized air, there will be high speeds of air flow in the tank. When the valve is opened, the speed and direction of the Streamline flow will change with time resulting in moving high speeds of Streamline flow which ends on the walls of the tank.

Question 2 : (A) Surface Tension increases with increasing temperature.

The above statement is false.

surface tension decreases when temperature increases because cohesive forces decrease with an increase of molecular thermal activity. The influence of the surrounding environment is due to the adhesive action liquid molecules have at the interface.

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