Work and Energy Unit Joule

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1. Feb 4, 2016

Work unit is said to be Joule and Energy unit is also Joule. Work formulas in F x S ( Force x Displacement) .
We know
1 J = 1 F x `1 s
Now Energy is also measured in Joule(J)
So can we state :
E = 1 F x 1 s as 1 J = 1 F x 1 s
that is
E = W

Then why work and energy are different by definition and meaning

2. Feb 4, 2016

QuantumQuest

A small glitch, 1J = 1N x 1s.

What do you mean by that? A very "rough" statement back from high school times, is "Energy of a body, is the ability to do work". Now, what are the definitions you refer to?

3. Feb 4, 2016

nasu

I am not sure if you mean to correct a glitch or to present one. :)
The Joule is not Nxs (Newton times second).

The OP meant Force x distance when he/she wrote 1J= 1F x 1s (by s probably meaning distance, displacement).

4. Feb 4, 2016

Well is W = E ? I am not going by definition but rather its unit of measurement which in this case is Joule (for both Work & Energy)? So why we state that work is said to be done when a is force applied on a body and it displaces while energy is ability or capacity to do work - why are the unit of measurement same for both work / energy - JOULE?

5. Feb 4, 2016

Svein

Because work and energy is two sides of the same coin. If you lift a boulder (10kg) up 1m, it means that:
• You have performed an amount of work = m⋅g⋅h = 10⋅9.81⋅1J = 98J
• The boulder has gained an amount of potential energy = m⋅g⋅h = 10⋅9.81⋅1J = 98J

6. Feb 4, 2016

QuantumQuest

Yes, sorry for the typo, I meant N x m - of course, in SI units.

Work expresses energy transmission or transformation of energy, from one form to another. So, they have the same unit of measurement.
As for the energy concept itself, I recommend this great insight by DaleSpam https://www.physicsforums.com/insights/what-is-energy/.

Last edited: Feb 4, 2016
7. Feb 4, 2016

ZapperZ

Staff Emeritus
Work is a form of energy
Potential energy is a form of energy
Kinetic energy is a form of energy

They ALL have the same dimension and SI units.

The similar way as

Electrostatic force is a form of force
Gravitational force is a form of force
Spring force is a form of force
Tension is a form of force
Frictional force is a form of force

They all have have the same dimension and SI units of N.

Zz.

8. Feb 5, 2016