Center of pressure (fluid mechanics)In fluid mechanics, the center of pressure is the point where the total sum of a pressure field acts on a body, causing a force to act through that point. The total force vector acting at the center of pressure is the surface integral of the pressure vector field across the surface of the body. The resultant force and center of pressure location produce an equivalent force and moment on the body as the original pressure field. Pressure fields occur in both static and dynamic fluid mechanics.
Velocity factorThe velocity factor (VF), also called wave propagation speed or velocity of propagation (VoP or of a transmission medium is the ratio of the speed at which a wavefront (of an electromagnetic signal, a radio signal, a light pulse in an optical fibre or a change of the electrical voltage on a copper wire) passes through the medium, to the speed of light in vacuum. For optical signals, the velocity factor is the reciprocal of the refractive index.
Mohr's circleMohr's circle is a two-dimensional graphical representation of the transformation law for the Cauchy stress tensor. Mohr's circle is often used in calculations relating to mechanical engineering for materials' strength, geotechnical engineering for strength of soils, and structural engineering for strength of built structures. It is also used for calculating stresses in many planes by reducing them to vertical and horizontal components.
Rock musicRock is a broad genre of popular music that originated as "rock and roll" in the United States in the late 1940s and early 1950s, developing into a range of different styles from the mid-1960s, particularly in the U.S. and the United Kingdom. It has its roots in 1940s and 1950s rock and roll, a style that drew directly from the blues and rhythm and blues genres of African-American music and from country music. Rock also drew strongly from genres such as electric blues and folk, and incorporated influences from jazz, classical, and other musical styles.
Sill (geology)In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or along the direction of foliation in metamorphic rock. A sill is a concordant intrusive sheet, meaning that it does not cut across preexisting rock beds. Stacking of sills builds a sill complex and a large magma chamber at high magma flux. In contrast, a dike is a discordant intrusive sheet, which does cut across older rocks.
AnticlineIn structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the location where the curvature is greatest, and the limbs are the sides of the fold that dip away from the hinge. Anticlines can be recognized and differentiated from antiforms by a sequence of rock layers that become progressively older toward the center of the fold.
Rock and rollRock and roll (often written as rock & roll, rock 'n' roll, or rock n roll) is a genre of popular music that evolved in the United States during the late 1940s and early 1950s. It originated from African-American music such as jazz, rhythm and blues, boogie-woogie, gospel, jump blues, as well as country music. While rock and roll's formative elements can be heard in blues records from the 1920s and in country records of the 1930s, the genre did not acquire its name until 1954.
Hydraulic jumpA hydraulic jump is a phenomenon in the science of hydraulics which is frequently observed in open channel flow such as rivers and spillways. When liquid at high velocity discharges into a zone of lower velocity, a rather abrupt rise occurs in the liquid surface. The rapidly flowing liquid is abruptly slowed and increases in height, converting some of the flow's initial kinetic energy into an increase in potential energy, with some energy irreversibly lost through turbulence to heat.
Folk rockFolk rock is a genre of rock music with heavy influences from English folk and American folk music. Combining the elements of folk and rock music, it arose in the United States, Canada, and the United Kingdom in the mid-1960s. In the U.S., folk rock emerged from the folk music revival. Performers such as Bob Dylan and the Byrds—several of whose members had earlier played in folk ensembles—attempted to blend the sounds of rock with their pre-existing folk repertoire, adopting the use of electric instrumentation and drums in a way previously discouraged in the U.
Action-angle coordinatesIn classical mechanics, action-angle variables are a set of canonical coordinates that are useful in characterizing the nature of commuting flows in integrable systems when the conserved energy level set is compact, and the commuting flows are complete. Action-angle variables are also important in obtaining the frequencies of oscillatory or rotational motion without solving the equations of motion. They only exist, providing a key characterization of the dynamics, when the system is completely integrable, i.
