Weapons in the context of "Mechanical design"

The law of war is the part of international law that regulates the conditions for initiating war (jus ad bellum) and the conduct of hostilities (jus in bello). Laws of war define sovereignty and nationhood, states and territories, occupation, and other critical terms of law. Among other issues, the modern laws of war address the declarations of war; acceptance of surrender and the treatment of prisoners of war; the principles of distinction, as well as military necessity and proportionality; and the prohibition of certain weapons that cause unnecessary or excessive suffering.

The law of war is considered distinct from other bodies of law—such as the domestic law of a particular belligerent to a conflict—which may provide additional legal limits to the conduct or justification of war. The term law of war, or jus in bello, overlaps to some degree with opinio juris (also referred to as customary law), but refers to a very specific body of international law composed of customary and treaty-based law.

Mechanical engineering is the study of physical machines and mechanisms that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, and maintain mechanical systems. It is one of the oldest and broadest of the engineering branches.

Mechanical engineering requires an understanding of core areas including mechanics, dynamics, thermodynamics, materials science, design, structural analysis, and electricity. In addition to these core principles, mechanical engineers use tools such as computer-aided design (CAD), computer-aided manufacturing (CAM), computer-aided engineering (CAE), and product lifecycle management to design and analyze manufacturing plants, industrial equipment and machinery, heating and cooling systems, transport systems, motor vehicles, aircraft, watercraft, robotics, medical devices, weapons, and others.

A gun is a device that propels a projectile using pressure or explosive force. The projectiles are typically solid, but can also be pressurized liquid (e.g. in water guns or cannons), or gas (e.g. light-gas gun). Solid projectiles may be free-flying (as with bullets and artillery shells) or tethered (as with Tasers, spearguns and harpoon guns). A large-caliber gun is also called a cannon. Guns were designed as weapons for military use, and then found use in hunting. Now, there are guns, e.g., toy guns, water guns, paintball guns, etc., for many purposes.

The means of projectile propulsion vary according to designs, but are traditionally effected pneumatically by a high gas pressure contained within a barrel tube (gun barrel), produced either through the rapid exothermic combustion of propellants (as with firearms), or by mechanical compression (as with air guns). The high-pressure gas is introduced behind the projectile, pushing and accelerating it down the length of the tube, imparting sufficient launch velocity to sustain its further travel towards the target once the propelling gas ceases acting upon it after it exits the muzzle. Alternatively, new-concept linear motor weapons may employ an electromagnetic field to achieve acceleration, in which case the barrel may be substituted by guide rails (as in railguns) or wrapped with magnetic coils (as in coilguns).

A random checkpoint is a military and police tactic. In a military context, checkpoints involve the setup of a hasty roadblock by mobile truck- or armored vehicle-mounted infantry to disrupt unauthorized or unwanted movement or military activity and to check for valid identification and search for contraband, fugitives, or weapons that are not permitted in civilian hands. Random checkpoints are set up to achieve surprise, as opposed to known permanently located checkpoints, which suspects could avoid. They are often established in locations where they cannot be observed by approaching traffic until it is too late to withdraw and escape without being observed.

Patrol car-equipped police units regularly use random checkpoints to detect drivers who are suspected of impaired driving. Police also use hastily set up roadblocks to check cars and car trunks when they are pursuing an armed and dangerous fugitive. As with military checkpoints, sobriety checkpoints and fugitive roadblock searches are located in an area where drivers cannot see the checkpoint until it is too late to withdraw, and checkpoints are only set up on a temporary basis.

The War of the Worlds is a science fiction novel by English author H. G. Wells about an attempted invasion of Earth by beings from the planet Mars with much greater intelligence and more advanced weapons than humans. The Martians intend to eliminate mankind and conquer Earth because their own older and smaller world has reached the "last stage of exhaustion". It was written between 1895 and 1897, and serialised in Pearson's Magazine in the UK and Cosmopolitan magazine in the US in 1897. The full novel was first published in hardcover in 1898 by William Heinemann. The War of the Worlds is one of the earliest stories to detail a conflict between humankind and an extraterrestrial race. The novel is the first-person narrative of an unnamed protagonist in Surrey and his younger brother who escapes to Tillingham in Essex as London and Southern England are invaded by Martians. It is one of the most commented-on works in the science fiction canon.

The plot is similar to other works of invasion literature from the same period and has been variously interpreted as a commentary on the theory of evolution, imperialism, and Victorian era fears, superstitions and prejudices. Wells later noted that inspiration for the plot was the catastrophic effect of European colonisation on the Aboriginal Tasmanians. Some historians have argued that Wells wrote the book to encourage his readership to question the morality of imperialism. In the preface to his collected works in 1933, Wells explained: "My early, profound and lifelong admiration for [Jonathan] Swift...is particularly evident in a predisposition to make the stories reflect upon contemporary political and social discussions", adding "The War of the Worlds like The Time Machine was another assault on human self-satisfaction", both being "consciously grim, under the influence of Swift's tradition".

In military science, force multiplication or a force multiplier is a factor or a combination of factors that gives personnel or weapons (or other hardware) the ability to accomplish greater feats than without it. The expected size increase required to have the same effectiveness without that advantage is the multiplication factor. For example, if a technology like GPS enables a force to accomplish the same results as a force five times as large without GPS, then the multiplier is five. Such estimates are used to justify the investment for force multipliers.