The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. At 20 °C (68 °F), the speed of sound in air is about 343 metres per second, or one kilometre in 2.91 s or one mile in 4.69 s. It depends strongly on temperature as well as the medium through which a sound wave is propagating. At 0 °C (32 °F), the speed of sound in air is about 331 m/s. More simply, the speed of sound is how fast vibrations travel.
The Packard Hawk is a model of automobile. It was the sportiest of the four Packard-badged Studebakers produced in 1958, the final year of Packard production.
The S-5 is a rocket weapon developed by the Soviet Air Force and used by military aircraft against ground area targets. It is in service with the Russian Aerospace Forces and various export customers. It is based on the R4M, a German design from World War 2.
The Mil Mi-4 is a Soviet transport helicopter that served in both military and civilian roles.
The Morgan Roadster is a model produced by the Morgan Motor Company. It was introduced in 2004 replacing the Morgan Plus 8. The car is identical to its predecessor except for new modern Ford V6 mechanicals. The new engine develops similar power, though less torque, and is slightly lighter than the Rover V8 which results in increased performance and better fuel economy. Air conditioning is now standard on U.S. models. Like its predecessor, the chassis consists of a standard ladder frame design and is built from galvanised steel with five tubular or box section cross members. The body is built of steel and aluminum around an ash frame. Suspension is traditional Morgan slider type up-front and solid axle / leaf spring at the rear.
Boragh or Boraq is an Iranian-made armoured personnel carrier. Boragh is believed to be a reverse engineered and upgraded model of the Chinese Type 86 (BMP-1). The upgrades include a reduction in weight, a higher road speed, and stronger armor. The vehicle is fully amphibious and is fitted with an NBC protection system and infra-red night vision equipment.
The 122-mm howitzer D-30 is a Soviet howitzer that first entered service in 1960. It is a robust piece that focuses on the essential features of a towed field gun suitable for all conditions. The D-30 has a maximum range of 15.4 kilometers, or over 21 km using rocket-assisted projectile ammunition.
The Falaq-1 missile is an Iranian made rocket system. It was developed in the 1990s by Shahid Bagheri Industrial Group, which is part of the Aerospace Industries Organization.
The Ural-5323 is an 8×8 heavy-duty off-road truck specially designed for army service. It has been produced since 1989 by the Ural Automotive Plant located in Miass, Russia.
The WZ-551 is a Chinese wheeled infantry fighting vehicle family. The name WZ-551 actually covers two families of vehicles with the official designations in the People's Liberation Army (PLA) – Type 90 and Type 92. Over 3,000 WZ-551s are in service with the PLA, where they are used by medium mechanized infantry units.
The Bristol Pullman was a British prototype passenger aircraft developed from the Braemar triplane heavy bomber.
The Avro Type E, Type 500, and Type 502 made up a family of early British military aircraft, regarded by Alliott Verdon Roe as his firm's first truly successful design. It was a forerunner of the Avro 504, one of the outstanding aircraft of the First World War.
The Walid is an Egyptian wheeled armored personnel carrier based on the BTR-40. It was built by the Kader Factory for Developed Industries. It entered production in 1960 and was first deployed by the Egyptian Army during the Six-Day War.
The Tatra 70 is a Czechoslovak luxury car that was made by Tatra at Kopřivnice from 1931 to 1937. It succeeded the Tatra 31.
The Naze'at 6-H and Naze'at 10-H/Mushak-120/Iran-130 are two Iranian long-range artillery rockets with ranges of about 100 km. The Naze'at 10-H is larger, more powerful, and has a longer range than the Nazeat 6-H. Like Iran's similar shaped Zelzal rockets, Naze'at rockets do not have a guidance system. Both systems are also widely known without the -H suffix, as the Naze'at 6 and Naze'at 10. The Iranians also have developed another 500 kg version called the Mushak-160 with 160 km range.
The South African Railways Class 6 4-6-0 of 1893 was a steam locomotive from the pre-Union era in the Cape of Good Hope.
The LEAF Trike is an American ultralight trike that was designed and produced by Leading Edge Air Foils in the 1980s. The aircraft was supplied as a kit for amateur construction.
The Mahindra Maxximo is a mini truck and a microvan that was manufactured by the Indian automaker Mahindra & Mahindra.
The STREIT Group Spartan is an armoured personnel carrier designed and built by STREIT Group; it is also license produced by KrAZ in Kremenchuk, Ukraine.
The P2 is an Indonesian armored car produced by PT Sentra Surya Ekajaya.
Sudan 
