Why are work and energy different even though they have the same units?

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PrakashPrasad
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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
 
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PrakashPrasad said:
We know
1 J = 1 F x `1 s

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

PrakashPrasad said:
Then why work and energy are different by definition and meaning

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?
 
QuantumQuest said:
A small glitch, 1J = 1N x 1s.

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).
 
QuantumQuest said:
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?
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?
 
PrakashPrasad said:
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?
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
 
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nasu said:
The Joule is not Nxs (Newton times second)

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

PrakashPrasad said:
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?

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/.
 
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PrakashPrasad said:
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?

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.
 
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QuantumQuest said:
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/.
Work expresses energy transmission or transformation of energy - got it thanks
 
ZapperZ said:
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.
Thanks for the details