What units are equivalent to a Joule?
- One newton-meter is a joule of energy.
- Lifting a full 12-oz can of soda one foot (11.42 inches) requires about a joule.
- Pulling the pull tab on that can of soda also requires about a joule of energy.
- In a US gallon of gasoline there are potentially 142 million joules available for propelling an automobile.
What is a Joule and what does it measure?
joule, unit of work or energy in the International System of Units (SI); it is equal to the work done by a force of one newton acting through one metre. Named in honour of the English physicist James Prescott Joule, it equals 10 7 ergs, or approximately 0.7377 foot-pounds.
What is the unit breakdown of a Joule?
The joule is said to be a derived unit, in that it is obtained from the base units kilograms, meters, and seconds. The amount of energy required to lift an apple 1 meter (3.3 feet) is roughly equivalent to 1 Joule. It can be regarded as a newton-meter — a force of 1 newton exerted over a distance of 1 meter (3.3 feet).
What does one joule equal to?
What is the Joule equal to? One joule equals the work done (or energy expended) by a force of one newton (N) acting over a distance of one meter (m). One newton equals a force that produces an acceleration of one meter per second (s) per second on a one kilogram (kg) mass. Therefore, one joule equals one newton•meter.
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What is the unit of energy?
Energy Units. Energy is generally defined as the potential to do work or produce heat. This definition causes the SI unit for energy is the same as the unit of work – the joule (J). Joule is a derived unit of energy and it is named in honor of James Prescott Joule and his experiments on the mechanical equivalent of heat.
How many cals are in a joule?
It is equal to the energy transferred to an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre. 1 joule = 0.239 Calories.
What is a joule?
What is Joule (unit J) – Energy Unit – Definition. Joule is a derived unit of energy. It is equal to the energy transferred to an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre. Thermal Engineering.
How fast does a 50 kg object move?
The kinetic energy of an object with mass 1 kg moving at √2 ≈ 1.4 m/s. The kinetic energy of a 50 kg object (e.g. human) moving very slowly – approximately 0.72 km/h. The energy required to lift a medium-size apple ( 100 g) 1 meter vertically from the surface of the Earth.
Is energy a physical quantity?
Since energy is a fundamental physical quantity and it is used in various physical and engineering branches, there are many energy units in physics and engineering.
Overview
The joule is the unit of energy in the International System of Units (SI). It is equal to the amount of work done when a force of 1 newton displaces a mass through a distance of 1 metre in the direction of the force applied. It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule (1818–1889).
Definition
In terms of SI base units and in terms of SI derived units with special names, the joule is defined as
One joule can also be defined by any of the following:
• The work required to move an electric charge of one coulomb through an electrical potential difference of one volt, or one coulomb-volt (C⋅V). This relationship can be used to define the volt.
• The work required to produce one watt of power for one second, or one watt-second (W⋅s) (comp…
History
The cgs system had been declared official in 1881, at the first International Electrical Congress. The erg was adopted as its unit of energy in 1882. Wilhelm Siemens, in his inauguration speech as chairman of the British Association for the Advancement of Science (23 August 1882) first proposed the Joule as unit of heat, to be derived from the electromagnetic units Ampere and Ohm, in cgs units equivalent to 10 erg. The naming of the unit in honour of James Prescott Joule (1818…
Practical examples
One joule represents (approximately):
• The amount of electricity required to run a 1 W device for 1 s.
• The energy required to accelerate a 1 kg mass at 1 m/s through a distance of 1 m.
• The kinetic energy of a 2 kg mass travelling at 1 m/s, or a 1 kg mass travelling at 1.41 m/s.
Multiples
Zeptojoule 160 zeptojoule is about one electronvolt. The minimal energy needed to change a bit at around room temperature – approximately 2.75 zJ – is given by the Landauer limit. Nanojoule 160 nanojoule is about the kinetic energy of a flying mosquito. Microjoule The Large Hadron Collider (LHC) produces collisions of the microjoule order (7 TeV) per particle. Kilojoule Nutritional food labels in most countries express energy in kilojoules (kJ). One square metre of the Earth receive…
Conversions
1 joule is equal to (approximately unless otherwise stated):
• 10 erg (exactly)
• 6.24150974×10 eV
• 0.2390 cal (gram calories)
• 2.390×10 kcal (food calories)
Newton-metre and torque
In mechanics, the concept of force (in some direction) has a close analogue in the concept of torque (about some angle):
A result of this similarity is that the SI unit for torque is the newton-metre, which works out algebraically to have the same dimensions as the joule, but they are not interchangeable. The General Conference on Weights and Measures has given the unit of energy the name joule, but ha…
Watt-second
A watt-second (symbol W s or W⋅s) is a derived unit of energy equivalent to the joule. The watt-second is the energy equivalent to the power of one watt sustained for one second. While the watt-second is equivalent to the joule in both units and meaning, there are some contexts in which the term "watt-second" is used instead of "joule", such as in the rating of photographic electronic flash units.