The "strongest" human muscle

Since three factors affect muscular strength simultaneously and muscles never work individually, it is misleading to compare strength in individual muscles, and state that one is the "strongest". But below are several muscles whose strength is noteworthy for different reasons.

* In ordinary parlance, muscular "strength" usually refers to the ability to exert a force on an external object—for example, lifting a weight. By this definition, the masseter or jaw muscle is the strongest. The 1992 Guinness Book of Records records the achievement of a bite strength of 4,337 N (975 lbf) for 2 seconds. What distinguishes the masseter is not anything special about the muscle itself, but its advantage in working against a much shorter lever arm than other muscles.

* If "strength" refers to the force exerted by the muscle itself, e.g., on the place where it inserts into a bone, then the strongest muscles are those with the largest cross-sectional area. This is because the tension exerted by an individual skeletal muscle fiber does not vary much. Each fiber can exert a force on the order of 0.3 micronewton. By this definition, the strongest muscle of the body is usually said to be the quadriceps femoris or the gluteus maximus.

* A shorter muscle will be stronger "pound for pound" (i.e., by weight) than a longer muscle. The myometrial layer of the uterus may be the strongest muscle by weight in the human body. At the time when an infant is delivered, the entire human uterus weighs about 1.1 kg (40 oz). During childbirth, the uterus exerts 100 to 400 N (25 to 100 lbf) of downward force with each contraction.

* The external muscles of the eye are conspicuously large and strong in relation to the small size and weight of the eyeball. It is frequently said that they are "the strongest muscles for the job they have to do" and are sometimes claimed to be "100 times stronger than they need to be." However, eye movements (particularly saccades used on facial scanning and reading) do require high speed movements, and eye muscles are exercised nightly during rapid eye movement sleep.

* The statement that "the tongue is the strongest muscle in the body" appears frequently in lists of surprising facts, but it is difficult to find any definition of "strength" that would make this statement true. Note that the tongue consists of sixteen muscles, not one.

* The heart has a claim to being the muscle that performs the largest quantity of physical work in the course of a lifetime. Estimates of the power output of the human heart range from 1 to 5 watts. This is much less than the maximum power output of other muscles; for example, the quadriceps can produce over 100 watts, but only for a few minutes. The heart does its work continuously over an entire lifetime without pause, and thus does "outwork" other muscles. An output of one watt continuously for eighty years yields a total work output of two and a half gigajoules.

Motorcycle land speed record

The motorcycle land speed record is the fastest speed achieved by a motorcycle on land. It is standardized as the speed over a course of fixed length, averaged over two runs in opposite directions.

First set, unofficially, by Glenn Curtiss in 1903,[1] the first officially-sanctioned FIM record was not set until 1920. There was controversy over the 1930 record, when OEC claimed to be fastest, on the basis of a publicity photo taken before a Zenith went quicker. "It was quite a while before the controversy died down.

Jet-engine trike
The fastest record certified by the FIM is that set in 1964 by the jet-propelled tricycle Spirit of America. It set three absolute land speed records, the last at 526.277 mph (846.961 km/h). While such records are usually validated by the Fédération Internationale de l'Automobile, the FIA only certifies vehicles with at least four wheels, while the FIM certifies two- and three-wheelers.

Fastest propeller-driven aircraft

A number of aircraft have claimed to be the fastest propeller-driven aircraft. This article presents the current record holders for several sub-classes of propeller-driven aircraft that hold recognized, documented speed records. (FAI) records are the basis for this article. Other contenders and their claims are discussed, but only those made under controlled conditions and measured by outside observers. Pilots during World War II sometimes claimed to have reached supersonic speeds in propeller-driven fighters during emergency dives, but these speeds are not included as accepted records.

Propeller versus jet propulsion
Aircraft that use propellers as their prime propulsion device constitute a historically important subset of aircraft, despite limitations inherent in their speed. Aircraft powered by piston engines get all of their thrust from the propeller driven by the engine. All aircraft prior to World War II used piston engines to drive propellers, so all Flight airspeed records prior to 1944 were necessarily set by propeller-driven aircraft. Rapid advances in jet engine technology during World War II meant that no propeller-driven aircraft would ever again hold an absolute air speed record. Shock wave formation in propeller-driven aircraft at speeds near sonic conditions, impose limits not encountered in jet aircraft.

Jet engines, particularly turbojets, are a type of gas turbine configured such that most of the work available results from the thrust of the hot exhaust gases. High bypass turbofans that are used in all modern commercial jetliners, and most modern military aircraft, get most of their thrust from the internal fan which is powered by a gas turbine in much the same way as a turboprop. Coupling such a gas turbine with a propeller gives a turboprop engine. The hot exhaust gas from a turboprop engine can give a small amount of thrust, but the propeller is the main source of thrust.

Turboprops
The Tupolev Tu-114, a large aircraft with four turboprop engines, has a maximum speed of 870 km/h (Mach 0.73, 541 mph). The 11,000 kW (14,800 shp) Kuznetsov NK-12 turboprop engines designed for the Tu-95 (and used to power the derivative Tu-114) are the most powerful turboprops ever built and drive large contra-rotating propellers. This engine-propellor combination gives the Tu-114 the official distinction of being the fastest propeller-driven plane in the world, a record it has held since 1960.

Probably the fastest aircraft ever fitted with an operating propeller was the experimental McDonnell XF-88B, which was made by installing a Allison T38 turboshaft engine in the nose of a pure jet-powered XF-88 Voodoo. This unusual aircraft was intended to explore the use of high-speed propellers and achieved supersonic speeds. This aircraft is not considered to be propeller-driven since most of the thrust was provided by two jet engines.

An oft-cited contender for the fastest propeller-driven aircraft is the XF-84H Thunderscreech. This aircraft is named in Guinness World Records, 1997, as the fastest in this category with a speed of 1002 km/h (623 mph, Mach 0.83).[5] While it may have been designed as the fastest propeller-driven aircraft, this goal was not realized due to its inherent instability. [6] This record speed is also inconsistent with data from the National Museum of the United States Air Force, which gives a top speed of 837 km/h (520 mph, Mach 0.70).