Rotational speed

Counterclockwise rotations about the center point where a complete rotation is equal to 1 turn.

Object rotating around an axis is the number of turns of the object divided by time, specified as revolutions per minute (rpm), cycles per second (cps), radians per second (rad/s), etc.

- Rotational speed
Counterclockwise rotations about the center point where a complete rotation is equal to 1 turn.

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Counterclockwise rotations about the center point where a complete rotation is equal to 1 turn.

Revolutions per minute

Number of turns in one minute.

Number of turns in one minute.

Counterclockwise rotations about the center point where a complete rotation is equal to 1 turn.

It is a unit of rotational speed or the frequency of rotation around a fixed axis.

Speed can be thought of as the rate at which an object covers distance. A fast-moving object has a high speed and covers a relatively large distance in a given amount of time, while a slow-moving object covers a relatively small amount of distance in the same amount of time.

Speed

Object is the magnitude of the rate of change of its position with time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity.

Object is the magnitude of the rate of change of its position with time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity.

Speed can be thought of as the rate at which an object covers distance. A fast-moving object has a high speed and covers a relatively large distance in a given amount of time, while a slow-moving object covers a relatively small amount of distance in the same amount of time.

Rotational speed (or angular speed) involves the number of revolutions per unit of time.

Pacific National diesel locomotives in Australia showing three body types, cab unit (front), hood unit (middle) and box cab (rear)

Locomotive

Rail transport vehicle that provides the motive power for a train.

Rail transport vehicle that provides the motive power for a train.

Pacific National diesel locomotives in Australia showing three body types, cab unit (front), hood unit (middle) and box cab (rear)
A Victorian Railways R class steam locomotive in Australia
A China Railways HXD1D electric locomotive in China
Wainwright SECR Class P on the Bluebell Railway, England
VR Class Tk3 steam locomotive in the town of Kokkola in Central Ostrobothnia, Finland
Trevithick's 1802 locomotive
The Locomotion No. 1 at Darlington Railway Centre and Museum
The 1887 Daimler draisine
The 1902 Maudslay Petrol Locomotive
An early Diesel-mechanical locomotive at the North Alabama Railroad Museum
World's first useful diesel locomotive (a diesel-electric locomotive) for long distances SŽD Eel2, 1924 in Kyiv
A German DB Class V 200 diesel-hydraulic locomotive at Technikmuseum, Berlin
Union Pacific 18, a gas turbine-electric locomotive preserved at the Illinois Railway Museum
Southern Railway (UK) 20002 was equipped with both pantograph and contact shoes
Werner von Siemens experimental DC electric train, 1879
Baltimore & Ohio electric engine, 1895
A prototype of a Ganz AC electric locomotive in Valtellina, Italy, 1901
A London Underground battery-electric locomotive at West Ham station used for hauling engineers' trains
A narrow gauge battery-electric locomotive used for mining
A Soviet steam-diesel hybrid locomotive TP1
Bombardier ALP-45DP at the Innotrans convention in Berlin

However, a turbine's power output and efficiency both drop dramatically with rotational speed, unlike a piston engine, which has a comparatively flat power curve.

A Henry rifle, the first successful lever action repeating rifle

Rifle

Long-barreled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves cut into the bore wall.

Long-barreled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves cut into the bore wall.

A Henry rifle, the first successful lever action repeating rifle
Names of parts of the M1 Garand rifle, World War II era, from US Army field manual
Rifling in a .35 Remington microgroove rifled barrel
Girdled bullet and twin rifle groove of the Brunswick rifle, mid-19th century
The method developed by Delvigne for his rifles, with the lead bullet being supported by a wooden sabot at its base.
British-made Minié rifle used in Japan during the Boshin war (1868–1869).
Loading mechanism of the Chassepot
Colt Model 1855 Carbine
Czechoslovak rifle vz. 24
Remington Model 700 in .30-06 Springfield with mounted telescopic sight and suppressor
Benchrest shooting with a Mauser rifle

Bullets leaving a rifled barrel can spin at a rotational speed of over 100,000 revolutions per minute (rpm) (or over about 1.67 kilohertz, since 1 RPM = 1/60 Hz).

Polish double Olympic champion Tomasz Majewski

Shot put

Track and field event involving "putting" a heavy spherical ball—the shot—as far as possible.

Track and field event involving "putting" a heavy spherical ball—the shot—as far as possible.

Polish double Olympic champion Tomasz Majewski
Czechoslovak shot putter Plíhal at the 1957 East German Indoor Athletics Championships
Shot putter at the University of Nebraska, 1942, showing the circle and stop board
Czechoslovak shot putter Jiří Skobla showing the correct technique for keeping the shot near the neck
Shot put area

Another purpose of the spin is to build up a high rotational speed, by swinging the right leg initially, then to bring all the limbs in tightly, similar to a figure skater bringing in their arms while spinning to increase their speed.

Moment arm diagram

Torque

Newton-metre .

Newton-metre .

Moment arm diagram
The torque caused by the two opposing forces Fg and −Fg causes a change in the angular momentum L in the direction of that torque. This causes the top to precess.
Torque curve of a motorcycle ("BMW K 1200 R 2005"). The horizontal axis shows the speed (in rpm) that the crankshaft is turning, and the vertical axis is the torque (in newton metres) that the engine is capable of providing at that speed.

For example, if rotational speed (revolutions per time) is used in place of angular speed (radians per time), we multiply by a factor of 2 radians per revolution.

A Wankel engine with its rotor and geared output shaft.

Wankel engine

Type of internal combustion engine using an eccentric rotary design to convert pressure into rotating motion.

Type of internal combustion engine using an eccentric rotary design to convert pressure into rotating motion.

A Wankel engine with its rotor and geared output shaft.
The Mazda RX-8 sports car is the last production car to date to be powered by a Wankel engine.
Norton Classic air-cooled twin-rotor motorcycle
The Wankel KKM motorcycle: The "A" marks one of the three apices of the rotor. The "B" marks the eccentric shaft, and the white portion is the lobe of the eccentric shaft. The distance between "A" and "B" remains constant. The shaft turns three times for each rotation of the rotor around the lobe and once for each orbital revolution around the eccentric shaft.
The first DKM Wankel engine designed by Felix Wankel, the DKM 54 (Drehkolbenmotor), at the Deutsches Museum in Bonn, Germany: the rotor and its housing spin
The first KKM Wankel Engine designed by Hanns Dieter Paschke, the NSU KKM 57P (Kreiskolbenmotor), at Autovision und Forum, Germany: the rotor housing is static.
Mazda's first Wankel engine, precursor to the 10A, at the Mazda Museum in Hiroshima, Japan
Mercedes-Benz C111 was fitted with a four-rotor Wankel engine
This 1972 GM rotary engine cutaway shows twin rotors.
Apex seals, left NSU Ro 80 Serie and Research and right Mazda 12A and 13B
Rolls Royce R6 two stage rotary compression ignition engine
Rolls-Royce R1C compression ignition prototype.
Mazda RX-8 Hydrogen RE hydrogen fuelled rotary engined car
NSU Wankel Spider, the first line of cars sold with a rotor Wankel engine
Mazda Cosmo, the first series two rotor Wankel engine sports car
Mazda 787B
Norton Interpol2 prototype
Wankel RC2-60 Aeronautical Rotary Engine
Diamond DA20 with a Diamond Engines Wankel
Sikorsky Cypher Unmanned aerial vehicle (UAV) powered with a UEL AR801 Wankel engine
Structure of a series-hybrid vehicle. The grey square represents a differential gear. An alternative arrangement (not shown) is to have electric motors at two or four wheels.
Mazda2 EV prototype
UEL UAV-741 Wankel engine for a UAV
Ogura Wankel Air conditioning system compressor

Since Wankel engines operate at a relatively high rotational speed, at 6,000rpm of output shaft, the Rotor makes only 2,000 turns.

Mariner 1

The first spacecraft of NASA's interplanetary Mariner program.

The first spacecraft of NASA's interplanetary Mariner program.

Mariner II trajectory projected on the ecliptic plane.
Diagram of Mariner 1
The communications station at Woomera
Atlas Agena with Mariner 1

The planet's rotation rate was uncertain, though JPL scientists had concluded through radar observation that Venus rotated very slowly compared to the Earth, advancing the long-standing (but later disproven ) hypothesis that the planet was tidally locked with respect to the Sun (as the Moon is with respect to the Earth).

A sphere rotating (spinning) about an axis

Rotation

Circular movement of an object around an axis of rotation.

Circular movement of an object around an axis of rotation.

A sphere rotating (spinning) about an axis
Rotation (angular displacement) of a planar figure around a point
Rotational Orbit v Spin
Relations between rotation axis, plane of orbit and axial tilt (for Earth).
Star trails caused by the Earth's rotation during the camera's long exposure time.
Euler rotations of the Earth. Intrinsic (green), Precession (blue) and Nutation (red)
The principal axes of rotation in space

The speed of rotation is given by the angular frequency (rad/s) or frequency (turns per time), or period (seconds, days, etc.).

Darwin Airline Saab 2000 in Etihad Regional livery taking off at Düsseldorf Airport in 2014

Saab 2000

Twin-engined high-speed turboprop airliner built by Swedish aircraft manufacturer Saab.

Twin-engined high-speed turboprop airliner built by Swedish aircraft manufacturer Saab.

Darwin Airline Saab 2000 in Etihad Regional livery taking off at Düsseldorf Airport in 2014
Saab 2000 cockpit
BA CityFlyer Saab 2000 parked at London City Airport (2016)
PenAir Saab 2000
Polet Airlines Saab 2000
Pakistan Air Force Saab 2000 AEW equipped with Erieye radar system
Saab 2000 cabin

The Dowty-Rotol propellers are 12.5 ft in diameter, and they have a slow rotational speed of 1,100 rpm at takeoff and 950 rpm in cruise.