![]() ![]() An object will always move in the direction of the greater force. An accelerating object can be speeding up or slowing down. Although acceleration is commonly used to describe an object that is speeding up, the scientific definition of acceleration means changing speed. 2.5, the buoyant force (B) is equal to the weight of the water displaced by the red block.Īn object accelerates when the forces on that object are unequal. This concept is known as Archimedes’ Principle, and it explains why objects sink or float. The buoyant force of the water is equal to the weight of the water displaced. He observed that the volume of water pushed out of a tub, or displaced, by an object was equal to the volume of the object. In the third century B.C., the Greek philosopher Archimedes was the first to describe buoyancy. The buoyant force (B) of water pushes up. ![]() The force due to gravity is greater on objects that are more massive, or weigh more. The gravitational force on an object is also called weight. 2.5, the gravitational force (G) is proportional to the mass of the red block. The gravitational force (G) of the earth pulls downward and is proportional to the mass of an object. Vertical-up-and-down-movement of water masses in the ocean can be explained in terms of two forces. The motion of any object is due to forces, which are pushes or pulls. When comparing two samples of water with the same salinity, or mass, the water sample with the higher temperature will have a greater volume, and it will therefore be less dense. ![]() The warmer the water, the more space it takes up, and the lower its density. This is represented by the increase in the size of the box from Fig. When the water is heated, it expands, increasing in volume. When the same amount of water is heated or cooled, its density changes. The density of water can also be affected by temperature. When comparing two samples of water with the same volume, the water sample with higher salinity will have greater mass, and it will therefore be more dense. The more salt there is dissolved in the water, the greater its salinity. Salinity describes how much salt is dissolved in a sample of water. This is represented by the addition of red spheres and blue cubes to the box from Fig. When salt is dissolved in fresh water, the density of the water increases because the mass of the water increases. Adding additional matter to the same volume also increases density, even if the matter added is a different type of matter (Fig. If volume increases without an increase in mass, then the density decreases (Fig. 1\,\texty) below it.If the amount of matter is increased without changing the volume, then the density increases (Fig. ![]() Plasma will not be discussed in depth in this chapter because plasma has very different properties from the three other common phases of matter, discussed in this chapter, due to the strong electrical forces between the charges. At high temperatures, molecules may disassociate into atoms, and atoms disassociate into electrons (with negative charges) and protons (with positive charges), forming a plasma. There exists one other phase of matter, plasma, which exists at very high temperatures. In this chapter, we generally refer to both gases and liquids simply as fluids, making a distinction between them only when they behave differently. When placed in an open container, gases, unlike liquids, will escape. This makes gases relatively easy to compress and allows them to flow (which makes them fluids). In contrast, atoms in gases are separated by large distances, and the forces between atoms in a gas are therefore very weak, except when the atoms collide with one another. Because the atoms are closely packed, liquids, like solids, resist compression an extremely large force is necessary to change the volume of a liquid. When a liquid is placed in a container with no lid, it remains in the container. That is, liquids flow (so they are a type of fluid), with the molecules held together by mutual attraction. This occurs because the atoms or molecules in a liquid are free to slide about and change neighbors. Liquids deform easily when stressed and do not spring back to their original shape once a force is removed. A gas must be held in a closed container to prevent it from expanding freely and escaping. (c) Atoms in a gas move about freely and are separated by large distances. Forces between the atoms strongly resist attempts to compress the atoms. (b) Atoms in a liquid are also in close contact but can slide over one another. Figure 14.2 (a) Atoms in a solid are always in close contact with neighboring atoms, held in place by forces represented here by springs. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |