What Are the Key Concepts of Mass, Pressure, and Buoyancy in the Atmosphere?

[Krivanka]

1) What is the mass of a column of air that has a cross-sectional area of 1

square centimeter and that extends from sea level to the top of the atmosphere?
What is the weight of this air column?
What is the pressure at the bottom of this column?

2) Is the value for atmosphere pressure at the surface of the Earth constant?

Explain.

3)How does the pressure at the bottom of the 76-cm column of mercury in a

barometer compare with the pressure due to the weight of the atmosphere?

4)When you drink liquid through a straw, it is more accurate to say the liquid is

pushed up the straw rahter than sucked up the straw. What exactly does the

pushing? Explain.

5) Why will a vacuum pump not operate for a well that is deeper than 10.3m?

6)The atmosphere does not ordinarily crush cans. Yet it will crush a can after it

has been heated, capped, and cooled. Why?

7)Why can an aneroid barometer be used to measured altitude?

8)When air is compressed, what happens to its density?

9)a) How great is the buoyant force on a balloon that weighs 1 N when it is suspended by buoyancy in air?
b) what happens in the buoyant force decreases?
c) What happens if the uoyant force increases?

10) When the speed of a fluid flowing in a horizontal pipe increases, what happens to the internal pressure in the fluid?

11)a)What are streamlines?
b)Is the pressure greater or less in regions where streamlines are crowded?

12)Does Bernoulli's principle provide a complete explanation for wing lift, or is there some other significant factor?

13)Why does a spinning ball curve in flight?

14)Small bubbles of air are released by a scuba diver deep in the water. As the bubbles rise, they become larger, smaller or stay about the same size? Explain.

15)It is easy to breathe when snorkeling with only your face beneath the surface of the water, but quite difficult to breathe when you are submerged nearly a meter, and nearly impossible when you are more than a meter deep(even if your snorkel tube reaches the surface). Figure out why, and explain carefully.

Thanks Much love

 

[Adrian Baker]

Asking 15 wide ranging questions is NOT what the HWK forum is for. What exactly don't you get? Where is your working? What have YOU done to understand the subject?

Do a little research on the subject... and get back to us with your problems.

 

[M98Ranger]

1) The mass of the air column can be calculated by multiplying the cross-sectional area (1 square centimeter) by the height of the column, which is the height of the atmosphere (approximately 100 km). This gives a mass of 1.2 x 10^10 kg. The weight of this air column can be calculated using the equation W=mg, where m is the mass and g is the acceleration due to gravity. The weight is approximately 1.2 x 10^11 N. The pressure at the bottom of the column can be calculated using the equation P=F/A, where F is the weight and A is the cross-sectional area. This gives a pressure of 1.2 x 10^12 Pa.

2) No, the value for atmospheric pressure at the surface of the Earth is not constant. It varies depending on location and weather conditions. Atmospheric pressure is affected by factors such as temperature, humidity, and altitude.

3) The pressure at the bottom of a 76-cm column of mercury in a barometer is equal to the pressure due to the weight of the atmosphere. This is because a barometer is used to measure atmospheric pressure, and the height of the mercury column is directly related to the pressure exerted by the atmosphere.

4) When you drink liquid through a straw, it is more accurate to say that the liquid is pushed up the straw rather than sucked up. This is because when you suck on the straw, you are actually creating a vacuum in the straw, and the atmospheric pressure pushes the liquid up to fill the empty space.

5) A vacuum pump will not operate for a well that is deeper than 10.3m because at this depth, the weight of the air above the pump is too great for the pump to create a vacuum. This means that the atmospheric pressure is higher than the pressure the pump can create, making it impossible to pump out any air.

6) The atmosphere does not ordinarily crush cans because the pressure inside the can is equal to the pressure outside. However, when a can is heated, the air inside expands and pushes against the walls of the can, causing it to crush when it is cooled and the air inside contracts.

7) An aneroid barometer can be used to measure altitude because as altitude increases, the atmospheric pressure decreases. The aneroid barometer works by measuring the changes in atmospheric pressure, so it can be used to determine changes in altitude.

8