A joule-second is a unit of power over time called action or a unit of angular momentum. In physics, the action principle is an assertion about the nature of motion, from which the trajectory of an object subject to forces can be determined. ... In physics the angular momentum of an object with respect to a reference point is a measure for the extent to which, and the direction in which, the object rotates about the reference point. ...

A joule second

1 joule/second (J/s) or (JS) = 1 watt = 1 volt ampere = 1 Newton m/s. All these definitions are equivalent.

A joule is the mechanical equivalent of heat so a joule second is the mechanical equivalent of heat per second.

As a measure of "power" where power is energy over time equivalent to work over time: 1 Joule/second = 1 Watt = 1 N-m/s = 1.341 022 × 10-3 hp = 0.737 5621 ft-lb/sec. (where hp is horsepower and ft-lb is foot-pound)

Derivation

Power is defined as work (energy) divided by time. The unit of work is called a joule. The unit of time is normally a second. The unit of power is called a watt, and is defined as a joule/second. Voltage is defined as work (energy) divided by electrical charge. The unit of electrical charge is called a coulomb. One volt is defined as one joule/coulomb. Current is defined as electrical charge divided by time. An amp is defined as a coulomb/second. Power is also equal to voltage multiplied by the current. Therefore, The coulomb (symbol: C) is the SI unit of electric charge. ...

Power = (work/charge)(charge/time) = work/time (joule/coulomb)(coulomb/second) = joule/sec = wattage

Angular momentum

The angular momentum of an object is the integral with respect to time of the torque on the object. Torque in the SI system has the unit N·m, so angular momentum has the unit N·m·s, or J·s. In the informal MKS system, this unit is called a planck, and is about 0.7375 foot pound second (ft·lb·s). The joule-second is the unit used for Planck's constant. In physics, torque can be thought of informally as rotational force. Torque is measured in units of newton metres, and its symbol is Ï„. The concept of Torque, also called moment or couple, originated with the work of Archimedes on levers. ... In physics, the newton (symbol: N) is the SI unit of force, named after Sir Isaac Newton in recognition of his work on classical mechanics. ... The metre (Commonwealth English) or meter (American English) (symbol: m) is the SI base unit of length. ... The International System of Units (symbol: SI) (for the French phrase Système International dUnités) is the most widely used system of units. ... A commemoration plaque for Max Planck on his discovery of Plancks constant, in front of Humboldt University, Berlin. ...

See also

• Joule