The hydrodynamics of a nozzle refer to the study of fluid flow through a constricted passage. When a fluid passes through a nozzle, its velocity increases while its pressure decreases due to the principle of conservation of mass and energy. This acceleration of the fluid flow is governed by the Bernoulli's principle, which states that an increase in fluid velocity is accompanied by a decrease in pressure. Nozzles are commonly used in various applications such as in jet engines, spray nozzles, and hydraulic systems to control and manipulate fluid flow. **

Hydrodynamics is the study of fluid motion and the forces acting on fluids, including the behavior of liquids and gases in motion. It focuses on the movement of fluids and the forces that cause the movement, such as pressure and viscosity. Hydraulics, on the other hand, specifically deals with the behavior and use of fluids in engineering and technology, particularly in relation to the mechanical properties of liquids. It involves the study of the behavior of fluids at rest and in motion, as well as the design and operation of hydraulic systems, such as pumps and pipes. In summary, while hydrodynamics is a broader field that encompasses the study of fluid motion and forces, hydraulics is a more specialized area that focuses on the practical applications of fluid behavior in engineering and technology. **

In the physics of hydrodynamics, a task refers to a specific problem or challenge related to the behavior of fluids in motion. This could involve understanding the flow of water in rivers, the behavior of waves in the ocean, or the dynamics of fluids in pipes or channels. Tasks in hydrodynamics often involve applying principles of fluid mechanics to analyze and predict the behavior of fluids in various situations, such as calculating the forces acting on a submerged object or predicting the behavior of a fluid under different conditions. These tasks are essential for understanding and engineering systems involving fluid flow, such as in civil engineering, environmental science, and oceanography. **

The caricature of the summit conference in Helsinki shows the leaders of the United States and Russia, Donald Trump and Vladimir Putin, sitting at a table with Trump holding a puppet string attached to Putin. This caricature is a satirical representation of the perception that Trump is under the control or influence of Putin, suggesting that Putin is pulling the strings and manipulating Trump. The image reflects the controversy and speculation surrounding the relationship between the two leaders and the potential influence of Russia on the United States. **

A symposium is a formal gathering or meeting where experts in a particular field come together to discuss and exchange ideas on a specific topic. It is often organized as a series of presentations, panel discussions, and Q&A sessions, allowing participants to share their knowledge and insights with each other. Symposia are commonly held in academic and professional settings, providing a platform for networking, collaboration, and learning within a specific discipline or industry. **

"Der Kongress tanzt" is a German phrase that translates to "The Congress Dances" in English. The phrase originated from the Congress of Vienna in 1814-1815, where European diplomats and leaders gathered to reorganize Europe after the Napoleonic Wars. The phrase is a metaphor for the diplomatic and political maneuvering that took place during the Congress, likening it to a dance where participants carefully navigated their relationships and alliances. It reflects the complex and intricate nature of international diplomacy and negotiations during this historic event. **

A convention is a formal agreement or a set of accepted norms and practices that govern behavior in a particular context or industry. It is a customary way of doing things that is widely recognized and followed by a group of people. Conventions help to establish consistency, order, and predictability in social interactions or professional settings. They can vary across different cultures, societies, or fields of study. **

The G20 summit is a meeting of the leaders of the world's 20 largest economies, representing both developed and developing countries. The summit provides a platform for these leaders to discuss and coordinate on global economic issues, such as trade, finance, and development. It is an opportunity for countries to work together to address common challenges and promote global economic stability and growth. The G20 summit also serves as a forum for leaders to address pressing international issues, such as climate change, terrorism, and global health crises. **