Chapter 14

A. the principle that states that the buoyant force on an object in a fluid is an upward force equal to the weight of the volume of fluid that the object displaces

D. Archimedes' Principle

A. the pressure caused by the weight of the atmosphere

D. Atmospheric Pressure

A. the upward force that keeps an object immersed in or floating on a liquid

D. Buoyant Force

A. a nonsolid state of matter in which the atoms or molecules are free to move past each other, as in a gas or liquid

D. Fluid

A. the SI unit of pressure

D. Pascal

A. the amount of force exerted per unit area of a surface (root: means to press)

D. Pressure

A. Fluid

Q. A ___________ can be a liquid or a gas

A. Pascal

Q. A unit used to express atmospheric pressure is _____________

A. c- below the water line.

Q. An iceberg in water. At what point is water pressure greatest? a) above the water, b) at the water line, c) below the water. How much of the iceberg has a weight equal to the buoyant force?

A. a

Q. An object that is surrounded by a fluid will displace a volume of fluid that is a) equal to the object's own volume, b) less than the object's own volume, c) greater that the object's own volume, or d) denser than the object itself.

A. area = force/pressure. a = 1500/500, a=3. 2(3) = 1,500/p, p=230

Q. Calculate the area of a 1,500 N object that exerts a pressure of 500 Pa (500 N/m2). Then, calculate the pressure that the same object exerts over twice that area.

A. Density is mass per unit volume

Q. Describe density in terms of mass and volume.

A. No, some fish like sharks must swim constantly to keep from sinking.

Q. Do sharks have swim bladders?

A. There is more pressure at the bottom of an object because pressure increases with depth. This difference in pressure results in an upward buoyant force on the object.

Q. Explain how differences in fluid pressure create a buoyant force on an object.

A. The weight of the displaced water is equal to the buoyant force acting on an object. The weight of 250 mL of water is about 2.5 N.

Q. Explain how displacement is used to determine buoyant force.

A. At lower levels of the atmosphere, more fluid from above is being pulled by the Earth's gravitational force. So there is more pressure at lower levels of the atmosphere.

Q. Explain why atmospheric pressure changes as depth changes?

A. High pressure stays consistent on the liquid. When you suck out the air of the straw, you lower the air pressure inside the straw, so the high pressure of liquid moves into the low pressure of the straw.

Q. Explain why drinking through a straw shows that fluids flow from areas of high pressure to areas of low pressure.

A. Density = mass/volume. If an object has more mass per volume than water, it will sink.

Q. Explain why volume and mass affect whether an object will sink or float in the water.

A. increases

Q. Fluid pressure _____________ as depth increases

A. ballast tanks that can be opened to allow sea water to flow in. As water is added, the submarine's mass increases, but its volume stays the same. The overall density increases so that it can dive under the surface. Compression air is used to blow the water out of the tanks so it can rise.

Q. How can a submarine travel both on the water and under the water?

A. Fluids exert pressure by the bumping of particles that creates a forces called pressure.

Q. How do fluids exert pressure on a container?

A. from areas of high pressure to low pressure

Q. How do fluids flow?

A. pressure = force / area

Q. How do you calculate pressure?

A. Like a submarine, some fish adjust their overall density to stay at a certain depth in the water. The swim bladder is filled with gases that are produced in the fish's blood.

Q. How does a swim bladder enable a fish to float?

A. Density = mass/volume. If an object has more mass per volume than water, it will sink.

Q. How does an object's density help you determine whether the object will sink or float in water?

A. The fan creates low pressure inside the vacuum cleaner. The air in the high pressure outside rushes to the low pressure inside, creating a vacuum or suction.

Q. Inside all vacuum cleaners is a high-speed fan. Explain how this fan causes the vacuum cleaner to pick up dirt.

A. 2 m -- more fluid from above is being pulled by the Earth's gravitational force

Q. Is water pressure greater at a depth of 1 m in a large lake or at a depth of 2 m in a small pond? Explain your answer.

A. Density is the amount of matter in a given volume, or mass per unit volume. Mass is proportional to weight. Mercury has more mass - and weighs more - which exerts more pressure on the bottom of the container.

Q. Mercury is a liquid that has a density of 13.5 g/mL. Water has a density of 1.0 g/mL. Equal volumes of mercury and water are in identical containers. Explain why the pressures exerted on the bottoms of the containers are different.

A. Changing shape, changing mass, changing volume

Q. Name 3 methods that can be used to change the overall density of an object.

A. bouyant and gravitational

Q. Name the 2 forces that are acting on the dolphin.

A. pressure = force/area. 200 N

Q. The water in a glass has a weight of 2.4 N. The bottom of the glass has an area of 0.012 m square. What is the pressure exerted by the water on the bottom of the glass? Formula?

A. more pressure

Q. Water is denser than air, therefore water exerts __________ ________________ than air

A. When the buoyant force is greater than the weight of the object.

Q. What causes an object to buoy up?

A. force = pressure x area. 248750 N

Q. What force is exerted on 2.5 m square if the pressure is 99,500 Pa? Formula?

A. 1.00 g/cm3

Q. What is the density of liquid water?

A. Regular shape (cube or rectangular box) measure the sides and multiple (LxWxH). Irregular shapes use water displacement - the amount of water the object pushes aside.

Q. What is the difference in method for finding the volume of a regular solid and the volume of an irregular solid?

A. cubic centimeters (c3)

Q. What is the measurements of solids?

A. It's hollow! The hollow shape increases the volume of the ship. Remember that density is mass per unity volume. As volume increases, density decreases if the mass stays the same.

Q. What is the secret of the ship's shape?

A. 80%! At the top of the atmosphere, pressure is almost nonexistent.

Q. What percentage of the atmosphere's gases are found within 10km of the Earth's surface?

A. a fluid

Q. What takes the shape of it's container?

A. Because planes fly at the top of the atmosphere were there is almost no air pressure making it hard to breathe.

Q. When airplanes fly high in the atmosphere, why must they be pressurized for passenger safety?

A. Because there is also pressure inside your body that acts against the atmospheric pressure

Q. Why are you not crushed by atmospheric pressure?

A. pressure changes in the air chamber behind your eardrum

Q. Why do your ears "pop" in an airplane?

A. Lower, because the beach balls have added mass to the ship

Q. Will a ship loaded with beach balls float higher or lower in the water than an empty ship will? Explain your answer.

A. Buoyant force

Q. _______________________ is the upward force that fluids exert on objects.

A. Atmospheric pressure

Q. ________________________________ on an object is caused by the weight of the air above the object