CHAPTER:7 FORCES IN FLUIDS
SUMMARY
Chapter 7 will talk about how fluids affect pressure, buoyancy, and motion.
Section 1: Fluids and Pressure
VOCABULARY
1.) FLUID: A non solid state of matter in which the atoms or molecules are free to move past each other, as in a gas or liquid
2.) PRESSURE: The amount force exerted per unit area of a surface
3.) PASCAL: The SI unit of pressure (symbol,PA)
4.) ATMOSPHERIC PRESSURE: The pressure caused by the weight of the atmoshere
Summary
All fluids exert pressure, fluids include liquids and gases. Fluids can flow because the particles in fluids can move easily past each other. You can calculate pressure by using this example pressure= force/area, the SI unit for pressure is pascal. One pascal (1Pa) is the force of one newton exerted over an area of one square meter (1N/M2). The atmosphere is the layer of nitrogen, oxygen, and other gases that surrounds Earth. Earths atmosphere is held together by gravity which pulls the gases toward Earth. The pressure is exerted on everything on earth. Atmospheric pressure is exerted on everything on earth, including me and you, at sea level the atmospheric pressure is about 101,300 Newtons. The higher you go from sea level the less atmospheric pressure. Water is a fluid, so it exerts pressure like the atmosphere. Water pressure also increases as depth increases, the deeper a diver goes, the greater the pressure. The pressure increases because more water above the diver is being pulled by earths gravitational force. Also water is about 1,000 times denser than air, density is the amount of matter given in an volume. Pressure also affects your breathing,because fluids want areas of high pressure to low pressure. When you inhale, a muscle increases the space in your lungs, this expansion creates decreases pressure in your lungs. The pressure in your lungs becomes lower than the pressure outside, so that is why air rushes in.
PRESSURE BY DEPTH
In this photo shows that there is more pressure below the iceberg than there is on top.
fluid pressure
This picture to the left is explaining and showing how fluids react with more pressure as the object goes to a lower depth.
Section:2 Buoyant Force
Vocabulary
1.) Buoyant Force: the upward force that keeps an object immersed in or floating on a liquid.
2.) Archimedes principle: the principle that states that the buoyant force on an object in a liquid is an upward equal to the weight of the volume of fluid that the object displaces.
2.) Archimedes principle: the principle that states that the buoyant force on an object in a liquid is an upward equal to the weight of the volume of fluid that the object displaces.
Summary
Water exerts fluid pressure on all sides of an object. The pressure exerted horizontally on one side of the object. The pressure exerted horizontally on one side of the object is equal to to the pressure exerted on the opposite side. So only the net force is exerted at the top and at the bottom of an object. Pressure increases as depth increases, so the pressure at the bottom of the object is greater than the pressure at the top. Archimedes principle states that the buoyant force of an object is an upward force equal to the weight of the fluid that the object takes place of, or displaces. The weight of an object does not affect the buoyant force. An object will sink if its weight is greater than the buoyant force. An object floats only when the buoyant force on an object is equal to an objects weight. Why does an ice float on water? One answer to this is simple, it is less dense than water. But you can also change density, by just reshaping its form into a hollow form. An example of this would a ship floating on water even though steel is more dense.
buoyancy
In the picture shows buoyancy between the rubber duck and water.
Section 3:Fluids and Motion
VOCABULARY
1. BERNOULLI S PRINCIPLE: The principle that states that the pressure in a fluid decreases as the fluids velocity increases
2. LIFT: The pushing or pulling force exerted by the engine of an aircraft or rocket
3. DRAG:A force parallel to the velocity of the flow; it opposes the direction of an aircraft and, in combination with thrust, determines the speed of the aircraft.
4. PASCALS PRINCIPLE: The principle that states that fluid in equilibrium contained in a vessel exerts a pressure of equal intensity in all directions.
2. LIFT: The pushing or pulling force exerted by the engine of an aircraft or rocket
3. DRAG:A force parallel to the velocity of the flow; it opposes the direction of an aircraft and, in combination with thrust, determines the speed of the aircraft.
4. PASCALS PRINCIPLE: The principle that states that fluid in equilibrium contained in a vessel exerts a pressure of equal intensity in all directions.
Summary
Bernoullis principle states that the speed of a moving fluid increases, the fluids pressure decreases. His principle is at work in this example, a tennis ball is attached to a string and swung into a piece of water, instead of being pushed out of the water the ball is held in the water. This how create between the ball and the water. The amount of lift created by the planes wing is determined partly by the speed at which air travels around the wing. The speed of a plane is determined mostly by thrust. The amount of lift also depends on the size of the planes wings. You can think of two examples a jet and a glider. Fluids exert a force that opposes the motion of objects moving through fluids, this force is called drag. Drag is usually caused by an irregular flow of air, an irregular or unpredictable flow of fluids is known as turbulence. Lift is often reduced when turbulence causes drag. Hydraulic devices use pascals principle to move or lift objects. Liquids are used in hydraulic devices because liquids cannot be easily compressed, or squeezed , into smaller spaces. Examples of objects that use hydraulic devices include; cranes, forklifts, and bulldozers.
Hydraulic Device
In this picture shows an example of an hydraulic device. (bulldozer) Click here for more info on section 7
FLYING!!!!
In this shows the four components of flying, which include lift, drag, thrust, and gravity.